Bubo lacteus (Temminck 1820)

Die reuse-ooruil (Bubo lacteus) (ook bekend as Verreaux se ooruil) is 'n lid van die familie Strigidae en is die grootste uilspesie in Afrika. Hierdie uil word gereken as die wêreld se derde grootste uil, naas die Blakiston se visuil en Eurasiese ooruil.

Sien ook

• Alfabetiese lys van Suid-Afrikaanse voëls
• Lys van Suid-Afrikaanse voëls (Groepeer)
• Lys van Suider-Afrikaanse voëls volgens wetenskaplike name

Verwysings

Bubo lacteus ye una especie de búho africanu y la mayor especie de búho del mundu.

Descripción

El búho llechientu algama un llargor mediu de 66-71 cm, con un valumbu de 2 m y un pesu mediu de 4 kg. Son fácilmente estremables polos sos discos faciales ablancazaos con un perfil negru y párpagos rosados,^[2] los sos güeyos son anaranxaos y como munches especies de búhos presenta dos "cuernos" de plumes carauterísticos. El so plumaxe ye d'un color pardu escuru nel envés y d'un color gris maciu nel banduyu.

Distribución y hábitat

Esta especie puede atopase n'África al sur del Sahara, de normal en zones montiegues xuntu al calce de ríos y arroxos, raramente n'altores cimeros a 2000 m.

Conducta

Son cazadores nocherniegos y añeren n'árboles altos. Duermen llixeramente mientres el día, pero espierten con rapidez pa defendese de cualquier ataque o amenaza.

Alimentu

Como munches especies de búhos, empiecen a amosase activos col tapecer. Los exemplares adultos alimentar de llebres, mangostes y otros mamíferos de tamañu mediu-pequeñu. Son unu de los pocos depredadores que s'alimenten de puercoespín.^[3] Cerca de les ciudaes los sos principales preses son aguaróns y palombos. Tampoco refalguen la carroña.

Reproducción

El periodu de reproducción asitiar ente marzu y setiembre.^[4] Tres el apareamiento la fema pon dos güevos que guara mientres unos 40 díes. Permanez nel nial mientres tol periodu d'incubación y el machu encargar d'alimentala. El primera pitucu en eclosionar ye'l primeru en ser alimentáu, y si nun hai abondu alimentu, namái esti pitucu va sobrevivir. Namái en condiciones de bayura dambos pitucos salen alantre. N'ocasiones el pollu más nuevu ye taramiáu pol so hermanu mayor. Los pitucos dexen el nial a los nueve selmanes pero pueden permanecer al pie de los sos padres hasta tres meses.

Referencies

Enllaces esternos

• Verreaux's Eagle Owl videos on the Internet Bird Collection

• Wikimedia Commons tien conteníu multimedia tocante a Bubo lacteus.

Esta páxina forma parte del wikiproyeutu Aves, un esfuerciu collaborativu col fin d'ameyorar y organizar tolos conteníos rellacionaos con esti tema. Visita la páxina d'alderique del proyeutu pa collaborar y facer entrugues o suxerencies.

El duc lletós^[1] (Bubo lacteus) és un ocell de la família dels estrígids (Strigidae) que habita boscos i sabanes de la major part de l'Àfrica Subsahariana.

Referències

A Wikimedia Commons hi ha contingut multimèdia relatiu a: Duc lletós

Aderyn a rhywogaeth o adar yw Eryrdylluan Verreaux (sy'n enw benywaidd; enw lluosog: eryrdylluanod Verreaux) a adnabyddir hefyd gyda'i enw gwyddonol Bubo lacteus; yr enw Saesneg arno yw Verreaux’s eagle owl. Mae'n perthyn i deulu'r Tylluanod (Lladin: Strigidae) sydd yn urdd y Strigiformes.^[1]

Talfyrir yr enw Lladin yn aml yn B. lacteus, sef enw'r rhywogaeth.^[2]

Teulu

Mae'r eryrdylluan Verreaux yn perthyn i deulu'r Tylluanod (Lladin: Strigidae). Dyma rai o aelodau eraill y teulu:

Rhestr Wicidata:

rhywogaeth enw tacson delwedd Cordylluan Glaucidium passerinum Cordylluan Bolifia Glaucidium bolivianum Cordylluan Brasil Glaucidium brasilianum Cordylluan Ciwba Glaucidium siju Cordylluan dorchog Glaucidium brodiei Cordylluan fannog Glaucidium perlatum Cordylluan frongoch Glaucidium tephronotum Cordylluan Hardy Glaucidium hardyi Cordylluan resog Asia Glaucidium cuculoides Cordylluan y goedwig Glaucidium radiatum Cordylluan y Gogledd Glaucidium gnoma Cordylluan yr Andes Glaucidium jardinii

Gweler hefyd

• Rhestr Goch yr IUCN

Cyfeiriadau

Der Milchuhu (Bubo lacteus), auch Blassuhu genannt, ist eine in Afrika weit verbreitete Uhu-Art. Er kommt in sogenannten Galeriewäldern, Waldgebieten mit Lichtungen sowie dünn bewaldeten Savannen vor.

Er erreicht eine Körpergröße von 53 bis 61 cm und hat einen deutlich rundlichen Kopf. Das Obergefieder ist bräunlich. Eine Besonderheit sind die rosafarbenen Augenlider.

Zu seinen Beutetieren gehören Perlhühner, Felsenratten, Schliefer, Igel, Frankoline, Mäuse, Schlangen und Flughunde.

Der Milchuhu nistet gewöhnlich in den Horsten von Greifvögeln. Er nimmt auch die Nester des Hammerkopfs als Nistgelegenheit an. Nur gelegentlich nistet er auch in Baumhöhlen.

Die Brutzeit fällt in die afrikanische Trockenzeit, das Gelege besteht aus ein bis drei Eiern.

Literatur

• Claus König, Friedhelm Weick: Owls of the World. Christopher Helm, London 2008, ISBN 978-0-7136-6548-2

Weblinks

• Bubo lacteus in der Roten Liste gefährdeter Arten der IUCN 2008. Eingestellt von: BirdLife International, 2008. Abgerufen am 31. Januar 2009.
• Videos, Fotos und Tonaufnahmen zu Bubo lacteus in der Internet Bird Collection

Verreaux's eagle-owl (Ketupa lactea), also commonly known as the milky eagle owl or giant eagle owl,^[3] is a member of the family Strigidae. This species is widespread in sub-Saharan Africa. A member of the genus Ketupa, it is the largest African owl, measuring up to 66 cm (26 in) in total length. This eagle-owl is a resident primarily of dry, wooded savanna. Verreaux's eagle-owl is mainly grey in color and is distinguishable from other large owls by its bright pink eyelids, a feature shared with no other owl species in the world.^[4]

Verreaux's eagle-owl is a highly opportunistic predator equipped with powerful talons. Just over half of its known diet is composed of mammals but equal or even greater numbers of birds and even insects may be hunted locally, along with any other appropriately sized prey that is encountered.^[5][6] This species is considered of Least Concern by IUCN as it occurs over a wide range and has shown some adaptability to human-based alterations and destruction of habitat and adaptability to diverse prey when a primary prey species declines in a region. As a large, highly territorial species of owl, it does, however, occur at fairly low densities and some regional declines have been reported.^[1][4]

The common name commemorates the French naturalist Jules Verreaux. The type specimen that was later described by Temminck at the Rijksmuseum van Natuurlijke Historie was collected by Verreaux while he was still in his teens.^[7][8]

Taxonomy

There are no known subspecies in the Verreaux's eagle-owl, and there is remarkably little variation in their appearance across their considerable distribution.^[5] Reportedly, birds in the southern part of their range appear marginally larger on average but these size differences are quite subtle and may be considered as a mild case of Bergmann's rule.^[9] While genetic research has been undertaken for this species, its closest living relative in the genus Ketupa is not fully clear. At one time, the Verreaux's eagle-owl was mentioned as an owl with particularly mysterious genetic alliances among living owls.^[10] Per Konig & Weick (2008), the species with studied genetic markers found to be most closely related are a dark-eyed species pair of Asian eagle-owls, the spot-bellied (Ketupa nipalensis) and barred eagle-owls (Ketupa sumatrana), but these are not particularly closely related to the Verreaux's.^[4]

Among species with available genomes to study for DNA characteristics, it has been revealed that the fish owls, in particular the brown fish owl (Ketupa zeylonensis), is the third most closely related species to the Verreaux's.^[11] Notably, Konig & Weick did not test the DNA of other African eagle-owls that may bear relation to the Verreaux's eagle-owl based largely on their solid dark brown eyes, namely Fraser's (Ketupao poensis), greyish (Bubo cinerascens) and Shelley's eagle-owl, as opposed to other eagle-owls which have yellow to orange irises. Fraser's and Usambara eagle-owls also have a small amount of bare skin around their eyes but this tends to bluish in color and is not nearly as extensive as the pink seen in Verreaux's.^[4] Other large owls native to Africa, the fishing owls, also have uniform dark brownish eyes and are sometimes included with the genus Bubo but how closely related they are to modern eagle-owls is unclear.^[4][12] Pliocene fossil Bubo owls with clear similarities based on osteological characteristics to the modern Verreaux's eagle-owl (most are currently classified as Ketupa cf. lactea) from South Africa and Tanzania, indicate that the Verreaux's eagle-owl descended from slightly smaller ancestors that increased in size as they diversified from related species.^[13][14]

Description

Despite the alternative common name of giant eagle-owl, Verreaux's eagle-owl is not the largest owl or eagle-owl in the world. It is, however, a very large and powerful owl species. This species is both the largest owl found in Africa and the world's largest owl to occur in the tropics. Among all the world's owls, it is fourth heaviest living owl, after Blakiston's fish owl (Ketupa blakistoni), the Eurasian eagle-owl (Bubo bubo) and the tawny fish owl (Katupa flavipes). In addition, it is the fourth longest extant owl (measured from the bill to the tip of the tail), after the great gray (Strix nebulosa), Blakiston's fish and Eurasian eagle-owls.^{[4][15][16][17]} Based on body mass and wing chord length, Verreaux's eagle-owl is about the same size as "medium-sized" races of Eurasian eagle-owl, such as those from Central Asian steppe (B. b. turcomanus) and the Himalayas (B. b. hemachalana), slightly smaller than most northern Eurasian races, considerably smaller than Siberian and Russian eagle-owls, and somewhat larger than the smallest Eurasian eagle-owl subspecies, such as those from the Iberian Peninsula (B. b. hispanus) and the Middle East (B. b. omissus or nikolskii).^{[18][19][20][21][22]}

Verreaux's eagle-owl ranges from 58 to 66 cm (23 to 26 in) in total length.^[3][23] This species has been reported as having an average wingspan of 140 cm (4 ft 7 in), but Mikkola referenced this as the wingspan of a smaller male.^[3][24][12] The largest known wingspan from a wild female measured nearly 164 cm (5 ft 5 in).^[25] While female owls are almost always larger than males, Verreaux's eagle-owl stands out as one of the most sexually dimorphic living owl species, some studies showing the female can average 35% heavier than the male. In comparison, the females of the nominate subspecies of Eurasian eagle-owls and great horned owl (Bubo virginianus) are reported to average approximately 20% and 25% heavier than the males, respectively.^[15][26] The full range of reported body mass in the species ranges from 1,615 to 2,000 g (3.6 to 4.4 lb) in males against a body mass of 2,475–3,150 g (5.5–6.9 lb) in females.^[4][27][28] In one study, 4 males were found to have averaged 1,704 g (3.8 lb) while 6 females averaged 2,625 g (5.8 lb).^[4][15] Another study found 5 males to have averaged approximately 1,700 g (3.7 lb) while five females averaged 2,300 g (5.1 lb).^[3][29] Unusually large sizes have been claimed in captivity with claims that specimens measuring up to 75 cm (30 in) in length and 200 cm (6 ft 7 in) in wingspan but these are unverified and possibly misreported as these figures match the largest Eurasian eagle-owls.^[22] Males heavier than any in the wild have been verified in captivity to weigh up to 2,200 g (4.9 lb).^[27] Among standard measurements, the female is reported to measure from 447 to 490 mm (17.6 to 19.3 in), averaging 465 mm (18.3 in), in wing chord, 230 to 273 mm (9.1 to 10.7 in) in the tail, while the same measurements in the male are from 420 to 490 mm (17 to 19 in), averaging 448 mm (17.6 in), and from 220 to 275 mm (8.7 to 10.8 in) in tail length. In both sexes, the tarsus has measured 73 to 86 mm (2.9 to 3.4 in) and the bill (in a small sample) 51 to 54 mm (2.0 to 2.1 in).^[4][27] Based on wing chord size compared to body mass and other linear dimensions, the Verreaux's eagle-owl averages somewhat larger in the size of its wings relative to its body size than most other eagle-owls, excluding the Asian fish owls which are also relatively long-winged.^[4][27]

Overall, Verreaux's eagle-owl is a fairly uniform and somewhat pale gray, with light and fine brownish vermiculations on the underside. The back is more solidly light brown with white spots on the shoulder. The oval facial disc is paler, sometimes ranging into a whitish color, than the rest of the front side of the bird with strong black borders bracketing either side. One other feature that immediately distinguishes adult Verreaux's eagle-owls in good light are its pink eyelids. The ecological purpose of their colorful eyelids is not known; however, Brown (1965) opined that they replace the colorful yellow to orange eyes of eagle-owls in breeding and territorial displays, since they were very conspicuous in displaying males.^[4][5][30] Their eyes are dark-brown in color and like all eagle-owls, they have ear-tufts. The ear-tufts are blunter and smaller relative to those of other African eagle-owls. The ear-tufts of this species are relatively subtle and can be missed in the field, especially if they are held lax.^[8] In appearance, they are quite easily distinguished if seen well. They are much bigger and bulkier than most other co-occurring owls. The only eagle-owl species in range that approaches its size is the Shelley's eagle-owl (Ketupa shelleyi), which may (but is not confirmed to) co-exist with the Verreaux's in northern Cameroon and the southern sliver of the Central African Republic most likely in forest edge and mosaics, but that species is a much darker sooty colour overall with broad black bands on the underside. Shelley's eagle-owl also has considerably different habitat preferences, preferring deep, primary forests, and is much more rarely observed in the wild.^[4][8]

The next largest owl in sub-Saharan Africa is the Cape eagle-owl (Bubo capensis). The individual home ranges, if not habitats, of the Verreaux's and cape eagle-owls may abut in nearly every part of the latter's distribution. Even in its largest race (Mackinder's eagle-owl, B. c. mackinderi) the cape eagle-owl is around 30% lighter in body mass on average than the Verreaux's eagle-owl, not to mention it being markedly different in almost all outward characteristics.^[4][27] Pel's fishing owl (Scotopelia peli), which occurs in west, central and inland southern Africa and may co-exist with the Verreaux's eagle-owl in much of its range (despite favoring wetland and riparian zones surrounded by wooded areas), can attain similar sizes as the Verreaux's eagle-owl but is dramatically different in color (a rather brighter rufous-cinnamon hue) and lacks ear-tufts.^[12] In combination, the characteristics of their pink eyelids, dark eyes, relatively uniform plumage and extremely large size render the Verreaux's eagle-owl as nearly unmistakable.^[4][12][31]

Voice

The call of the Verreaux's eagle-owl is the deepest of any extant owl species and one of the deepest bird calls in the world, averaging slightly deeper than the calls of the Blakiston's and brown fish owls (Ketupu zeylonensis). The calls of Eurasian eagle-owls are less deep but are possibly louder and farther carrying.^[12][32] The male's song is an exceptionally deep gwok, gwok, gwonk-gwokwokwok gwokwokwok gwonk. The depth and quality of the song makes confusion by sound more likely with a leopard (Panthera pardus) than any other bird.^[5] The song is sometimes considered unmistakable.^[8] According to a study in Kenya, the voice is considered the second deepest bird call after the southern ground hornbill (Bucorvus leadbeateri), though that species has a fairly croaking call reminiscent of a large frog and in recordings appears to have a less sonorous call.^[5] Apparently, the song can carry up to 5 km (3.1 mi) away on quiet nights.^[4] The female's call is similar but higher pitched, as in all owls to some extent because the larger female tends to have a smaller syrinx.^[8][33] Like most Bubo owls, breeding pairs not infrequently call together but they are not as well-synchronized as the pair duets of spotted eagle-owls (Bubo africanus), which are often found in nearby ranges.^[5][8] The alarm calls of both sexes are often a sonorous whok or hook but variable grunting notes and raspy screams also seem to indicate alarm.^[4][8] Both the female and the young engage in high, piercing calls when begging for food at the nest (at which time the male does the food capture).^[4][34] One other vocalization recorded has included a raspy, drawn-out shrooooo-ooo-eh apparently uttered as a distraction display mainly by the male near the nest.^[5] While sound is important to some degree for inner-species relations and hunting behaviour to all owl species, the Verreaux's eagle-owl appears to have relatively small and uncomplicated ear openings compared to several smaller types of owl. This indicates that the auditory senses are relatively unimportant in this species compared to vision.^[35]

Distribution and habitat

Verreaux's eagle-owl is found through most of sub-Saharan Africa, though it is absent from most of the deep rainforests. The species is found at the highest densities in eastern and southern Africa. As this species avoids primary forests, it is found very spottily in west Africa. Their western distribution includes The Gambia, Senegal, Guinea and Sierra Leone.^[1][31] Eastward from those countries to the Central African Republic, the species is distributed in a narrow transitional zone between the Sahara and rainforests.^[1] Seemingly isolated populations occur in central Nigeria and central Mali.^[36][37] In south-western Africa, they range up to as far north as the southern parts of the Republic of the Congo and the Democratic Republic of the Congo, through most of Namibia (excluding the coastal regions) and northern South Africa.^[1][11] In east Africa, their distribution is more or less continuous from southern Sudan, Eritrea and inland Somalia down to South Africa as far as the region of the city of Durban.^{[1][38][39][40]}

This species inhabits mainly savanna with scattered trees and thorny vegetation. Verreaux's eagle-owls mainly inhabit rather dry regions, some bordering semi-arid areas.^[4][37] In central Mali, for example, near the extreme northwestern limit of the species range, the habitat that hosts these owls averages less than 55 cm (22 in) of rainfall annually.^[37] They also range into riverine forest adjacent to savanna and small, semi-open woodland surrounded by open country, though they are less likely to inhabit heavily wooded habitats.^[4][8] South African eagle-owls are not infrequently found around floodplains and marshes, which may provide the primary nesting habitat in some areas.^[41] In Uganda, they are largely associated with riparian woodlands.^[42][43] Verreaux's eagle-owl may live at nearly all elevations, from sea level to near the snow-line at around 3,000 m (9,800 ft) in elevation, such as in the Eastern Rift mountains. However, in general, they only sporadically inhabit rocky areas and so are generally very scarce in mountainous regions.^[4] The bushveld of southern Africa is near ideal habitat for Verreaux's eagle-owl and the species may be found at near peak numbers here.^[8] The species was historically rare to absent from the Kalahari desert, but the introduction by man of invasive trees like conifers, eucalyptus and acacias, irrigation areas and prey species has allowed them to spottily occupy this region.^[8][44][45]

Behavior

Verreaux's eagle-owls are nocturnal birds and roost by day in trees, with large, shaded horizontal branches of tall, old trees being preferred.^[4] In Kenya, the most often-used perch trees were Croton megalocarpus and invasive Eucalyptus.^[5] Elsewhere, Acacia trees may be used habitually.^[46] Despite normally choosing dense foliage to rest in, sometimes they may sit wherever their hunting path ends from the prior night, including relatively exposed perches.^[4][24] They reportedly sleep rather lightly and will awaken very quickly to defend themselves from attack in daylight hours.^[24] Family groups consisting of breeding pairs and their offspring frequently roost together and may engage in allopreening during this time.^[4] Reportedly some family groups include eagle-owls that had hatched up to three years prior, which if accurate is exceptional for any type of owl species.^[8][47] During extremely hot days, this species may flutter its throat for cooling purposes and has been known to bathe in rain and shallow water during extreme heat in the middle of the afternoon but usually drinks when possible during nighttime.^[4] Each breeding pair of Verreaux's eagle-owl defends a territory and these may be extremely large, ranging in size up to 7,000 ha (17,000 acres).^[8]

Food and feeding

Verreaux's eagle-owl is considered an avian apex predator, meaning it is at or near the top of the food chain and healthy adults normally have no natural predators. In many known aspects of its hunting behaviour, it is typical of the members of the genus Bubo. This species hunts predominantly in early evening; however, they have been observed to swoop on prey during daylight.^[4] They usually fly to a different perch from their daytime roost to use as their habitual hunting perch.^[4] Verreaux's eagle-owls mainly hunt by gliding down on their prey from a perch. However, hunting on the wing has been reported, even of flying insects.^[5] On occasion, they hunt by flying low over a bush to catch prey by surprise or dash on the wing into dense foliage or through forests to catch a galago or other arboreal prey item.^[4] They will also sometimes run after prey on the ground, flapping their wings rapidly as they walk, or wade into shallow waters to pin down fish. The wing size of eagle-owls in general limits their flying speed and abilities in the open and so they require perches to execute most of their hunting behaviour.^[12][48]

Even among the Bubo owls, most species of which are known to be highly opportunistic predators with indiscriminating diets, the Verreaux's eagle-owl is a particularly opportunistic predator. While earlier studies characterized great horned owl, one of the most well-studied members of the genus Bubo, as hunting whatever random species they first come across,^[49] more modern dietary studies have contrarily shown their prey selection is not completely random and that regionally they selected cottontails and hares as prey instead of other foods regardless of prey population trends and became regional specialists on such prey, to such an extent that it predictably causes owl population declines at times when leporid numbers decline.^[50][51] Furthermore, species-wide, great horned owls may select mammals as prey nearly 88% of the time.^[33] In contrast, studies have indicated that for the Verreaux's eagle-owl only around 56% of its diet is mammals and no single prey type predictably dominates their prey selection by biomass in multiple regions.^[5][48] To date, more than 100 prey species have been counted for this eagle-owl and, with only about half a dozen comprehensive dietary studies known to have been conducted, this probably only represents a small portion of the total prey selected.^[48] Estimated prey size for the species has ranged from insects weighing less than 5 g (0.18 oz) to ungulates weighing at least 10 kg (22 lb). This is the second broadest size range positively attributed to a single owl species for prey items after the Eurasian eagle-owl and the largest exceptional upper prey-size also after the Eurasian species.^{[6][48][52][53]}

Mammals

The prey type most often associated with Verreaux's eagle-owl are hedgehogs. It appears that this species is the only routine predator of hedgehogs in Africa, most other predators of small-to-medium-sized mammals choosing to pursue other abundant mammals without the hedgehog's prickly defenses.^[54] In both the southernmost, from the western cape of South Africa, and northernmost, a partial study of the foods at nests in central Mali, food studies for this species have found hedgehogs to be the most significant contributor of biomass in Verreaux's eagle-owl nests.^[37][48] The two known hedgehog prey species taken are the four-toed hedgehog (Atelerix albiventris), which averages 335 g (11.8 oz) in adults, in the north and the southern African hedgehog (Atelerix frontalis), which averages 350 g (12 oz) in adults, in the south.^[55][56] When capturing hedgehogs, the eagle-owl descends silently with its soft-comb wings and ambushes the hedgehog by imbedding its talons about the face. After death, the hedgehog is skinned of its prickly back before being consumed by either the eagle-owl itself or the young at the nest. This may result in over a dozen hedgehog skins being found around Verreaux's eagle-owl roosts near their nests.^{[8][37][48][57]} The same method of dealing with hedgehogs is utilized by the Eurasian eagle-owl, which is likewise reported as the only routine predator of hedgehogs in its native continent.^[4][58] Studies in other areas have shown that, while hedgehogs are seemingly taken opportunistically, they are at best secondary as contributors of prey both in quantity and biomass.^[6][46]

In general, the diet of Verreaux's eagle-owl is seemingly random and highly variable. Eagle-owl species from temperate zones may have no choice but to predate rodents which are rather small and this may require a nesting pair to capture up to a dozen rodents nightly.^[33][59][60] In comparison, the diversity and abundance of rodents is considerably greater in wild areas of sub-Saharan Africa and the Verreaux's eagle-owl seemingly ignores most small rodent species, with no rodent prey species known to average under 30 g (1.1 oz) in adult body mass.^{[5][6][46][48]} In Kenya, the most often recorded prey locally were Tachyoryctes mole-rats; however, these were recorded only slightly more often than other genera or species, including non-mammals.^[5] Several species of blesmol, a separate family also sometimes referred to as mole-rats, have also been recorded as prey.^[6][46][61] Several murid species have been hunted ranging in size from the 31 g (1.1 oz) southern multimammate mouse (Mastomys coucha) to the two non-native Rattus species, including the 360 g (13 oz) brown rat (Rattus norvegicus).^{[5][6][62][63][64]} Some larger rodents they've hunted have included the 529 g (1.2 lb) cape ground squirrel (Xerus inauris), the 786 g (1.7 lb) Gambian pouched rat (Cricetomys qambianus) and the 1,900 g (4.2 lb) lesser cane rat (Thryonomys gregorianus).^[5][63][65] The largest known rodent prey is the South African springhare (Pedetes capensis) at an average adult weight of 3,040 g (6.7 lb).^[48][63] Avery, et al. (1985) opined that springhares may be only taken as carrion as they claim it be too large for the eagle-owl to overpower and indeed at least one South African springhare was fed on as roadkilled carrion. However, Avery, et al. (1985) also acknowledged that adult monkeys of larger size have verifiably been taken alive by the eagle-owls, so it certainly should not be ruled out that they also take live springhares.^[6][48]

Many other mammals taken as prey by Verreaux's eagle-owl are seemingly any encountered except the much larger species, especially those that show a propensity for nocturnal or crepuscular activity. This species has hunted bats in several cases from the 8.1 g (0.29 oz) Lander's horseshoe bat (Rhinolophus landeri), the smallest known vertebrate prey species known for this eagle-owl, to Rousettus fruit bats that weigh over 150 g (5.3 oz).^[66] Most other mammalian prey recorded or inferred as hunted by Verreaux's eagle-owl tend to be considerably larger. Both the scrub hare (Lepus saxatilis) and the cape hare (Lepus capensis) have been reported as food, the scrub species estimated to average 2,740 g (6.0 lb) when taken.^[6][48] In parts of Kenya, the scrub hare can be a particularly significant contributor of biomass to the eagle-owl's diet.^[67] Other assorted mammalian prey species include the 540 g (1.2 lb) golden-rumped elephant shrew (Rhynchocyon chrysopygus) and the 3,800 g (8.4 lb) cape hyrax (Procavia capensis), although it is possible that juvenile hyraxes are rather more commonly taken than adults.^[68][69][70]

So far as is known, Verreaux's eagle-owl is the only living owl that preys upon multiple species of primate, although isolated incidents of predation (normally on young primates) has been reported in two to three other large, tropical owls.^{[4][33][48][71]} Multiple cases of predation against galagos have been reported, unsurprisingly as they represent all nocturnal primates in Africa, although they are seldom identified to species.^[5][6] Known galago prey species have ranged from the 85.3 g (3.01 oz) Thomas's bushbaby (Galagoides thomasi) to the 1,098 g (2.4 lb) brown greater galago (Otolemur crassicaudatus).^[5][72] Monkeys are also predated opportunistically. Particularly often reported in foods of the Verreaux's eagle-owl as primates go is the vervet monkey (Chlorocebus pygerythrus).^[72][73][74] Incidents of successful predation have included vervets that were half-grown, which the eagle-owl was able to fly off with (despite being about as heavy as the eagle-owl itself), and an adult vervet of an estimated weight of 4,000 to 5,000 g (8.8 to 11.0 lb), which an eagle-owl took on the ground and subsequently dismembered.^[5][46][48] However, considering the formidable gauntlet of predators that vervet monkeys face, the Verreaux's eagle-owl is one of its more minor predators and attacks on them may be considered incidental, due in part to the monkey's primarily diurnal activities.^{[75][76][77][78]} Other monkey species believed to be occasionally vulnerable to attacks include the blue monkey (Cercopithecus mitis), which is similar in size to the vervet, patas monkeys (Erythrocebus patas) and the young of the chacma baboon (Papio ursinus). Adult patas monkeys, averaging some 8,633 g (19.0 lb), can be even larger than vervet monkeys but whether they take prime adults of the species is questionable.^{[72][79][80][81]}

There are a few verified cases of Verreaux's eagle-owls feeding on ungulates; however, some authors such as Avery, et al. (1985) feel that these generally represent cases of scavenging on carrion. The remains of an adult grysbok (Raphicerus melanotis), weighing an estimated 10,670 g (23.5 lb), was opined with certainty to have been taken as carrion per this study.^[6] Steyn (1982) accepted that this species could take live prey weighing up to 10,000 g (22.0 lb) on rare occasions; however, he stated in a case of an adult common duiker (Sylvicapra grimmia) being fed on by an eagle-owl that the duiker was likely roadkill.^[48] Scavenging on carrion is generally a rare behaviour in owls and has been reported in only a few cases where large owls are exceptionally hungry.^[4][82] Live ungulates verified to have been hunted have included piglets of common warthogs (Phacochoerus africanus), which have an average birth weight of only 665 g (1.5 lb) but grow to over 2,000 g (4.4 lb) in just a couple weeks.^[48][82][83] Adult Kirk's dik-diks (Madoqua kirkii), one of the smallest antelope species at an average of 4,590 g (10.1 lb) have also been hunted by Verreaux's eagle-owl.^[84][85]

Among mammalian carnivores the bulk of predatory incidents have reportedly involved mongooses. Common, social species from savanna-edge such as the 710 g (1.6 lb) yellow mongoose (Cynictis penicillata) and the 725 g (1.6 lb) meerkats (Suricata suricatta) have been attacked, as well as larger, shy forest dwellers such as the 2,500 g (5.5 lb) Jackson's mongoose (Bdeogale jacksoni).^[86][87] An adult Meller's mongoose (Rhynchogale melleri) weighing about 2,200 g (4.9 lb) which was taken by a Verreaux's eagle-owl on the wing represents the second heaviest known object successfully flown with this species after the aforementioned half-grown vervet monkey.^[82] Other smallish carnivores known to fall prey to Verreaux's eagle-owls include the 292 g (10.3 oz) African striped weasel (Poecilogale albinucha) and its larger cousin, the 817 g (1.8 lb) striped polecat (Ictonyx striatus), which in one nest from the border of the Kalahari represented the sole prey species for a pair of eagle-owls.^{[6][88][89][90]} In southern Africa, both the cape genet (Genetta tigrina), averaging 1,732 g (3.8 lb), and the 1,600 g (3.5 lb) black-footed cat (Felis nigripes), the smallest felid in Africa, have been included amongst their prey.^{[91][92][93][94]} The Verreaux's eagle-owl is thought to be a threat to even larger carnivores, including the 4,150 g (9.1 lb) bat-eared fox (Otocyon megalotis) and the 10,000 g (22.0 lb) aardwolf (Proteles cristata), although whether healthy adults of the latter are in danger is doubtful.^{[95][96][97][98][99]} A scientifically-observed attack on an adult male African wildcat (Felis silvestris cafra), which can weigh more than about 4,500 g (9.9 lb), was aborted after the eagle-owl apparently deemed that the felid was too heavy to take flight with.^[100] However, domesticated cats of any size may fall prey to Verreaux's eagle-owl. At Lake Baringo Country Club in Kenya, this eagle-owl has apparently taken to habitually hunting outdoor cats, reportedly making the cats on the grounds highly skittish.^[101]

Birds

Verreaux's eagle-owl takes a diverse range of birds as prey. More than 50 avian prey species have been identified and they may locally exceed mammals in importance in the diet, somewhat unusually for eagle-owls.^[6][33] No one type of bird can be said to be predictably favored as prey and any avian species unfortunate enough to have a nighttime roost or nest that happens to be in an eagle-owl's foraging path may fall victim to this species. Many cases of predation involve nest robbery, with nestlings or fledglings being taken, although adult birds may be taken just as often, especially for species with less conspicuous nests.^[5][6][48] In South Africa's De Hoop Nature Reserve, it was found that birds were somewhat better represented by both number, 43.3% of remains, and biomass, 57.84% of remains, than mammals or any other prey group. The species best represented in biomass in the prior study was the black-headed heron (Ardea melanocephala) with several adults estimated to average 1,260 g (2.8 lb) being found among the prey remains.^[6] Other fairly common, largish herons are also known to fall prey at night to Verreaux's eagle-owl including the 873 g (1.9 lb) common egret (Ardea alba), the 1,443 g (3.2 lb) grey heron (Ardea cinerea) and the 975 g (2.1 lb) purple heron (Ardea purpurea).^{[15][101][102]}

Other medium-sized water birds known to have been represented in this species diet include the 1,008 g (2.2 lb) yellow-billed duck (Anas undulata), the 983 g (2.2 lb) African black duck (Anas sparsa), the 596 g (1.3 lb) African swamphen (Porphyrio madagascariensis) and the 825 g (1.8 lb) red-knobbed coot (Fulica cristata).^[5][6][103] Besides herons, another well-represented group of birds in the diet are galliforms. Perhaps the most widely preyed species reported from this group is the 1,229 g (2.7 lb) helmeted guineafowl (Numida meleagris), which may seasonally dominate the eagle-owl's food in Kenya.^[48][67] More modestly sized wild galliform species reported in the diet including the 96 g (3.4 oz) common quail (Coturnix coturnix) and the 390 g (14 oz) grey-winged francolin (Francolinus africanus).^[6][15] Domestic fowl, especially those allowed back to a semi-feral state and thus sleeping in the open as is prevalent in Africa, are taken when encountered, including chickens and peafowls.^[48][104]

Various upland birds recorded as prey include the 177 g (6.2 oz) Namaqua sandgrouse (Pterocles namaqua), the 350 g (12 oz) rock pigeon (Columba livia), the 84 g (3.0 oz) laughing dove (Streptopelia senegalensis), the 169 g (6.0 oz) Senegal coucal (Centropus senegalensis), the 49 g (1.7 oz) scaly-throated honeyguide (Indicator variegatus) and several species of hornbill, ranging in size from the 139 g (4.9 oz) northern red-billed hornbill (Tockus erythrorhynchus) to the 1,235 g (2.7 lb) silvery-cheeked hornbill (Bycanistes brevis).^{[6][15][37][82][105][106]} Among passerines, the most frequently taken are likely to be corvids, which are often favored by Bubo owls from around the world due to their large size, relatively open nests and frequently easy-to-find, communal nocturnal roosts. To date the cape crow (Corvus capensis) and pied crow (Corvus albus) are the corvids reported in dietary studies. In Ethiopia, thick-billed ravens (Corvus crassirostris), which at 1,500 g (3.3 lb) are possibly the heaviest corvid species in the world, mobbed them vigorously and seemed to consider them a primary threat.^[5][6][107] Smaller passerines are by no means ignored.^[108][109] White-eyes are among the more frequently taken smaller passerines, with the 10.9 g (0.38 oz) southern yellow white-eye (Zosterops anderssoni) being the smallest identified avian prey species, although penduline tits (Anthoscopus ssp.) are likely to be even smaller.^{[5][6][48][110]} The largest bird to be hunted by Verreaux's eagle-owl is complicated by the fact that they often take relatively small nestlings of larger species, such as ostriches (Struthio camelus) and grey crowned cranes (Balearica regulorum).^[48] The only avian prey items successfully attacked larger than other types of birds of prey (reviewed later) are likely bustards.^[4][6][48] Most predation records have reported on relatively small bustards, namely northern (Afrotis afraoides) and southern black korhaans (Afrotis afra), which average only 745 g (1.6 lb) and 690 g (1.5 lb), respectively.^[48][111] Larger species of bustard thought to be threatened by Verreaux's eagle-owl are the 4,790 g (10.6 lb) Denham's bustard (Neotis denhami) and the 8,430 g (18.6 lb) kori bustard (Ardeotis kori), although it is not clear whether adults (especially males) are attacked in the latter species.^{[48][111][112]}

Other prey

Reptiles and amphibians are occasional prey for Verreaux's eagle-owls. Various snakes have been included in their diet ranging from the small, innocuous brown house snake (Boaedon fuliginosus) at 31 g (1.1 oz) to large and venomous Egyptian cobras (Naja haje) weighing over 454 g (1.0 lb).^[5][6][113] Frogs were amongst the prominent prey recorded for suburban-breeding eagle-owls in South Africa, namely the African red toad (Schismaderma carens) and the guttural toad (Amietophrynus gutturalis). Unidentified frogs were fairly significant in the diet from Kenya.^{[5][104][114]} The largest herpetological prey known is the Nile monitor (Varanus niloticus), at a mean mature mass of 5,850 g (12.9 lb), these primarily diurnal reptiles can provide a fulfilling meal but can be hard to subdue even if ambushed unaware.^{[48][82][115][116]}

Predation on fish has been reported but no fish have been observed firsthand in dietary studies.^[48] A surprisingly wide range of invertebrates have been reported in the diet for this species. In some cases, they may prey on insects as small as termites and even smaller invertebrates have been recorded in pellets such as oribatid mites and Sarcophaga flies, but are likely consumed incidentally while eating a larger item, either from carrion or the stomach of the prey itself.^[6][117] Unidentified scorpions, spiders and millipedes have also been reported in their foods.^[5][48] Most attacks on insects involve large ground beetles or dung beetles. Verreaux's eagle-owl has been known to feed on dung beetles among herds of African buffalo (Syncerus caffer) by night, boldly diving below the massive bovids’ legs, and will readily feed on beetles among elephant dung when available.^{[6][118][119]}

Interspecies predatory relations

Sub-Saharan Africa has many species of owl, although there is less species diversity than in some areas of similar latitude in the neotropics and south Asia.^[4][12] It also hosts the most species of eagle-owl with approximately eight "typical" Bubo species and all three fishing owl species as well.^[4][48] Due to the diversity here, there are a number of distinctions between habitat preference, primary prey types and body size among the eagle-owls of Africa.^[52][82] The three smallest species of this genus reside solely in Africa, the akun eagle-owl (Ketupa leucosticta), the greyish eagle-owl (Bubo cinerascens) and the spotted eagle-owl (Bubo africanus), in rough order of increasing size. These species are all primarily insectivores and are much reduced in the size and strength of their feet and talons compared to most other contemporary species, although the spotted eagle-owl can be locally specialized to feed on small rodents as well.^{[4][12][27][120]} While the akun is a primary forest-dweller as are the medium-sized Fraser's and Usambara eagle-owl and large Shelley's eagle-owl and thus is not likely to co-exist with Verreaux's eagle-owls except in rare cases, the northerly-distributed greyish eagle-owl (which was at one point considered merely a subspecies of the spotted) and the southerly-distributed spotted eagle-owl have much more similar habitat preferences to the Verreaux's species.^{[4][48][121][122]} Of the non-piscivorous owls in Africa, the Cape eagle-owl can have a somewhat broad diet and a capability to take large prey but is more specialized to feed on a narrow range of mammals, mole-rats often supplemented with rock hyrax, than the Verreaux's eagle-owl.^{[48][82][123]} The Cape eagle-owl has a fairly strong preference for nesting and hunting within the confines of rocky and mountainous habitats, whereas the Verreaux's is at best sporadic in such areas.^{[5][124][125][126]} In east Africa and South Africa, habitat degradation has allowed the more adaptable Verreaux's eagle-owl to move into areas inhabited by cape eagle-owls and has presented the possible issue of the Verreaux's competitively excluding the smaller species.^[124][127]

Outside of the genus Bubo, other owls in Africa are much smaller than Verreaux's eagle-owls and are more likely to be viewed as prey than competition. Among the small-to-mid-sized owls that have fallen prey to this species are the barn owl (Tyto alba) and the African grass owl (Tyto capensis), both of which average around 419 g (14.8 oz) in body mass in Africa, the 334 g (11.8 oz) marsh owl (Asio capensis) and the 216 g (7.6 oz) southern white-faced owl (Ptilopsis granti).^{[5][15][33][48][101]} The only verified interactions with other typical eagle-owls have been predatory, as the 645 g (1.4 lb) spotted eagle-owl has been recorded among their prey in a few cases.^[5][48] There are several owls with broadly similar habitat preferences from African scops owls (Otus senegalensis) to African wood owls (Strix woodfordii) that have not been reported as food but are almost certainly occasionally threatened by Verreaux's eagle-owls.^[48][82] As is commonly the case with eagle-owls, the Verreaux's eagle-owl is perhaps the most serious predatory threat to diurnal raptors in its range, most often ambushing raptors on their prominent nests upon nightfall and freely killing birds of prey of any age from nestlings to adults. Such prey is not quantitatively significant as a food source but since raptors as a rule are sparsely distributed the habitual visitation of a single or pair of Verreaux's eagle-owl can potentially be devastating to a local population.^[6][33][48] Among the species of small-to-medium-sized raptors known to be attacked are the 638 g (1.4 lb) African harrier-hawk (Polyboroides typus), the 675 g (1.5 lb) pale chanting goshawk (Melierax canorus), the 507 g (1.1 lb) African marsh harrier (Circus ranivorus), the 110 g (3.9 oz) scissor-tailed kite (Chelictinia riocourii), the 291.5 g (0.6 lb) African goshawk (Accipiter tachiro) the 875 g (1.9 lb) common buzzard (Buteo buteo) and the 640 g (1.4 lb) Wahlberg's eagle (Hieraaetus wahlbergi).^{[5][6][48][82][128]}

There are reports of Verreaux's eagle-owls attacking even larger raptorial birds. A case of the Verreaux's eagle-owl killing an adult Pel's fishing owl in Botswana was verified. At roughly 2,000 g (4.4 lb) in body mass, the fishing owl is of nearly the same size as the eagle-owl.^[129] Cases where they've attacked the nests of particularly large diurnal birds of prey have sometimes involved only nestlings being victimized, such as attacks on the hooded vulture (Necrosyrtes monachus) and the bateleur (Terathopius ecaudatus); none of the adults, which are about the same average adult body mass as the Verreaux's eagle-owls, have been reported as prey.^[48][130] However, in some even larger birds of prey, adults as well as nestlings and fledglings have been killed. Successful nighttime attacks have been reported on adults of the 2,810 g (6.2 lb) African fish eagle (Haliaeetus vocifer) and the 4,017 g (8.9 lb) secretarybird (Sagittarius serpentarius).^[48] In the Matobo Hills of Zimbabwe, the Verreaux's eagle-owl has been considered as one of the inferred predators of 4,195 g (9.2 lb) Verreaux's eagle (Aquila verreauxii), although whether adults or only nestlings are vulnerable is not definitely clear.^[131][132]

Other than these rare cases, larger birds of prey such as eagles are not usually harassed by Verreaux's eagle-owl and are more aptly viewed as competitors. In fact, the martial eagle (Polemaetus bellicosus) is sometimes regarded as the diurnal ecological equivalent of the Verreaux's eagle-owl.^[103] The martial eagle has rather similar habitat preferences to the eagle-owl and has a similarly broad, opportunistic diet.^{[48][133][134]} At roughly 4,200 g (9.3 lb) in average body mass, the martial eagle is roughly twice as heavy as Verreaux's eagle-owl and takes correspondingly large prey, its average prey weight range being 1,000 to 5,000 g (2.2 to 11.0 lb) and the eagles are capable of exceptionally taking prey up to nearly nine times their own weight, whereas most of the eagle-owls prey does not exceed 1,000 to 1,500 g (2.2 to 3.3 lb). Verreaux's eagle-owl is likely to give martial eagles a respectful space during daytime and there are no records of the two species harassing one another.^{[6][15][48][135]} Another particularly large and aggressive eagle, the crowned eagle (Stephanoaetus coronatus), is largely a forest-dweller and so is less directly a diurnal equivalent. There is a single recorded instance of an immature crowned eagle being aggressively displaced at night by an adult Verreaux's eagle-owl when it happened to encroach on the eagle-owl's territory but without bloodshed and eagle-owls would do well to avoid the exceptionally powerful eagle.^{[48][135][136]} Taken together, the Verreaux's, the Shelley's and the Cape eagle-owls could be seen as nocturnally replacing the eagle species of martial, crowned and Verreaux's eagles in the respective habitats of savanna, forest and rocky areas but their increasingly diminishing size in comparison to the diurnal eagles means that, generally speaking, less large-bodied prey is likely to be attacked.^{[48][82][135][137]} Despite its place near the top of the nocturnal avian food chain, in 2013 a remote wildlife camera videotaped a black-backed jackal (Canis mesomelas) attacking and killing a Verreaux's eagle owl at a watering hole.^[138] Similar rare successful attacks on great horned owls and Eurasian eagle-owls by smaller red foxes (Vulpes vulpes) have been reported, but in these cases the horned owl was mysteriously grounded and the eagle-owl was nesting in too-easily accessed sea cliffs. More often foxes are prey rather than predators for northern Bubo owls.^{[139][140][141][142][143]} Given that the Verreaux's eagle-owl is surprisingly bold about coming to their ground to, among other things capture beetles, feed on prey too large to carry in flight or, as is likely the case in the jackal attack, drink water, it is possible that the jackal was simply able to ambush an incautious eagle-owl rather than a grounded one.^[48][138] Perhaps even more unexpectedly, an adult bateleur was filmed killing a Verreaux's eagle-owl by day, though whether this was predation or a competitive or anti-predatory attack is unclear.^[144]

Breeding

In the heart of their distribution, i.e. east Africa, breeding activity in this species can peak any time from February to September, but can occur nearly any month at the species level.^[4][145] The timing of breeding is said to be correspondent roughly to the regional dry season, so averages earlier in the northern part of the range (before February) and later (July to September) in the southern part of the range such as Kenya and South Africa.^[5][37][48] In the northern part of the range, breeding season commenced in November in Mali, in November and December in Senegal, December in Equatorial Guinea and January in Nigeria.^[37][146] The monogamous pair is quite stable, most likely mating for life. As in most owls, a courtship display is both to establish mates for a newly mature pair of eagle-owls or to strength pair bonds prior to nesting.^[4][8][82] Vocalizations during courtship displays consist of relatively rapid and excited calling, hooting and whining. The pair during courtship will bow to one another, flick open their wings and preen each other's feathers, with the male taking the more active part in the courtship ritual.^[4][8] Like all raptorial birds, Verreaux's eagle-owls are strongly territorial.^[48] The pair will defend their territory by their song and sometimes (though rarely) through duets. The territories of Verreaux's eagle-owls can range up to 7,000 hectares in size, although average territory sizes are seemingly unknown.^[4][8][48]

Like great horned owls, but unlike Eurasian eagle-owls, the Verreaux's eagle-owls normally uses old nests built by other birds as their own nests. Usage of a nest site other than those constructed by other birds is considered rarer even than in the horned owl and is viewed as almost exceptional in some parts of this species range.^[4][5][37] Existent reports of this species building its own nest are certain to be dubious, as no known living owl builds a nest and only a small handful of owl species have been verified adding a small amount of nesting material to an existing surface or nest.^[4][5] They variety of bird nests they use is extreme. Large stick nests in sturdy trees are generally used.^[4] In southern Africa, recorded nest heights have ranged from 6 to 25 m (19 ft 8 in to 82 ft 0 in) off the ground.^[48] Like other Bubo owls, the large nest of large-bodied accipitrids are often popular for use, due to the often huge size and sturdiness of construction typical in this family, with the nest builders devoting up to four months to their construction.^[147] However, perhaps the constructor of nests that most often host Verreaux's eagle-owls are hamerkops (Scopus umbretta). In everywhere from Mali to South Africa the eagle-owl has been recorded using old nests built by this species.^[37][48] The unusual, massive nest is an enclosed circle of sticks with a side entrance that are often very large relative to the size of the hamerkop, a smallish, compact wading bird. Usually the eagle-owls nest on the flat top of the hamerkop nest rather than the interior which is usually too small for the eagle-owls to enter and this can provide a rather safe structure for the eagle-owl family to call home.^[37][48]

Other nest builders which are popular as hosts are vultures, eagles (at least eight species have built nests used by these eagle-owls), secretarybirds, crows and even much smaller birds such as weavers, which build huge communal nest structures which the eagle-owls then similarly nest on top of.^{[4][5][37][48][148]} Most nests are already abandoned when the Verreaux's eagle-owl take over it, in large accipitrids for example, many build alternate nests which are not used for years on end.^[48] However, if the nest is occupied, the Verreaux's eagle-owl pair readily displaces the occupants and sometimes feeds on the birds in them.^[48] Species known to be successfully displaced from their nests have ranged up in size to lappet-faced vultures (Torgos tracheliotos), which are more than three times heavier on average than the Verreaux's eagle-owl.^[48] In some cases, hamerkops have been known to try to defend their nest from the eagle-owls but are usually chased away.^[5] Verreaux's eagle-owls have been known to displace other opportunistic nest usurpers such as other owls and falcons in order to take over nest structures for themselves.^[5][37][149] In one case, a pair of eagle-owls nested on top of a hamerkop nest while the interior of the nest was occupied by Egyptian geese (Alopochen aegyptiacus), an unusual aggressive species of waterfowl that uses nests built by other species.^[48] In rare cases, Verreaux's eagle-owls have been recorded using large, old hollows, the stem of a palm tree or on a very dense tangle of creepers or orchids instead of birds' nests as a nesting site.^[4][48][110]

On average, the female lays two white eggs, which typically measure 62.6 mm × 51.4 mm (2.46 in × 2.02 in), with a range in height of 58 to 66 mm (2.3 to 2.6 in) and a range in width of 48 to 54 mm (1.9 to 2.1 in).^[4][48][150] The eggs weigh from 93 to 101.6 g (3.28 to 3.58 oz), the upper weight being the mean mass of the first egg and the lower weight being the mean mass of the second egg.^[4][12] The eggs are reportedly laid at up to 7 day intervals and may take up nearly seven days as well between hatching.^[4] Most nest reportedly contain two eggs, but some may contain only one, and no more than two has been recorded in this species.^[4][48][151] The adult female incubates the eggs for 33 to 39 days, the incubation stage being slightly longer than those of most other eagle-owls, at least the more northern species.^[4][37] On average at hatching, the young weigh about 60 to 70 g (2.1 to 2.5 oz).^[4] The weight of the nestling can triple within five days after hatching.^[37] Due to the extreme interval between the hatching of the first and the second egg, the older owlet is always considerably larger than the second. As is widely reported in different kinds of raptorial birds, the smaller chick usually dies in the nest.^[152] This may be due to starvation upon being outcompeted for food by the older chick or the smaller chick may be being attacked and killed by its older sibling. Usually the smaller chick is gone within two weeks after hatching in this species.^[4][48][128] In rare cases, both chicks are reared and survive to leave the nest, although there are no known cases of two fledglings resulting from a Verreaux's eagle-owl nest in southern Africa.^[37][48] The young are covered in off-white down from hatching on and the pink eyelids may become apparent within the first week of life.^[4][37] By three weeks of age, the chicks down will thicken and darken to a greyish colour with some barring present.^[48] By six weeks, the young eagle-owl will start to somewhat resemble an adult, replete with the blackish brackets on the facial disc of the adult but still being fairly downy, particularly about the head. Only a week later, almost all the down is likely to be moulted.^[37][48]

The mother Verreaux's eagle-owl remains on the nest for nearly the entire incubation period while the male hunts for food for both of them. During the brooding stage, which lasts about 20 days after hatching, the female is still fed by the male, but resumes hunting thereafter.^[4] During the incubation and brooding stage, the male usually roosts near the nest during the day while the female continually sits about the nest.^[48] After the brooding stage, the female normally takes to a perch within a dozen or so metres of the nest.^[37] Both parents may use a favor perch near the nest at which they dismantle prey into pieces that can be more easily consumed by their young, these may be called "plucking" perches where birds are more commonly eaten or "peeling" perches where hedgehogs are the most regular prey. Most dietary studies for the species have been from researching the pellets and skins under such perches.^[48][128] The female is an extremely tight sitter both while incubating and brooding, and may not even be displaced from the nest even if shouted at or the tree is struck.^[5][48] When intruders approach too closely, including other eagle-owls, potential predators and humans, the most common response of the parent Verreaux's eagle-owl is to grunt lowly, often raising its ear-tufts and bill-clapping.^[4][5] Both sexes may engage in distraction displays when the area near the nest is encroached, but it usually the male and most displays occur during nighttime but are possible at any time of day or night. During such displays, the adult will fly lover the ground with drooping wings, or alights and drags its wings and flaps about, often while bill-clacking and calling.^[5][48] Similar injury-feigning distraction displays have been recorded in the Eurasian eagle-owl and smaller owl species but are not known in most other Bubo species.^[33][153] In one case, feral dogs were successfully lured away from a young Verreaux's eagle-owl by its parents’ distraction display after the young bird had fallen to the ground.^[48] In rare cases, the parent eagle-owls will attack interlopers. In one such case, a person who picked up a young eagle-owl on the ground was severely injured after both parents attacked him.^[4][48]

On average, the young Verreaux's eagle-owl leaves the nest at around 62–63 days but cannot fly at this point. It may take roughly anywhere from another two weeks to a month after this before the fledgling is a competent flier.^[4][48] After leaving the nest, the fledgling is "remarkably inactive", making a minimum of effort to fly, and usually selecting a roost within a few feet of the nest which it has awkwardly climbed to or will drop to a large bush below the nest.^[4][48] In the nest, the chick will beg for food with a shrill or chittering noise, sometimes bobbing its head or swaying about and transferring its weight between its feet (sometimes called a "hunger dance") and it continues to rely on its parents for food well after leaving the nest.^[5][48] Sometimes after leaving the nest, the young eagle-owls are mobbed as are adults by other birds of prey and crows during the day, which is often heatedly directed at this species as adult eagle-owls regularly kill these birds at night. The young eagle-owl may dodge to denser branches to avoid being wounded during such attacks.^[5] Young Verreaux's eagle-owls may fall to the ground, often as a result of mobbing. If the young bird is discovered on the ground, it may feign death, lying prone with its head lax and its eyes closed. Even if picked up while death-shamming, the young eagle-owl may remain moribund. Upon being left without disturbance after "playing dead", the young Verreaux's eagle-owl will gradually open its eyes and return to a normal state.^[48]

It is not until they are about 5 months old do most young Verreaux's eagle-owl show the ability to capture prey for themselves. However, the stage at which the young of this species becomes independent appears remarkably variable. One ringed 9-month-old moved 24 km (15 mi) away from its nest area and was thus seemingly fully independent.^[4] On the other hand, Verreaux's eagle-owls of over half-a-year in age who presumably can fly and hunt on their own have been seen to linger and continue to beg its parents to be fed into the next breeding season, and may even be fed by their father while he is also feeding the mother and a new nestling.^[48] In Kenya, when a biologist fed a wild juvenile eagle-owl mole-rats and chicken heads in its nest area, the young eagle-owl apparently became remarkably confiding towards the person.^[46] The tendency of young eagle-owls to linger into the next breeding season sometimes results in "family groups" roosting together, a very unusual occurrence for an eagle-owl species. One such group consisted of five birds together, including two parents and three owls from the preceding past three years and apparently the younger eagle-owls even helped bring food for the chick once the egg hatched.^[8][46][48]

On average, sexual maturity in Verreaux's eagle-owls appears to be attained at three to four years of age.^[4] In most cases, a pair of Verreaux's eagle-owl is able to nest annually; however, in some cases they may nest only every two to three years, in probable situations of extreme food shortages.^[4][48] Annual mortality appears to be fairly low in this large owl species. Few species have been reported to hunt Verreaux's eagle-owls short of the aforementioned jackal attack, even nests have rarely been seen to be predated, although they may on rare occasions run foul of some predators such as larger felids with the ability to climb.^[46][48] That young birds usually leave the nest before they can fly would appear to endanger them but the threat and distraction display of parent eagle-owls are apparently often successful.^[48] Adult eagle-owls can appear nearly fearless, as they have been reported to stand their ground and engage in threat displays when encountered on or near the ground against much larger animals such as rhinoceroses and lions, and in such cases are apparently not approached further by the bigger animals although the eagle-owls could easily be killed by such animals if contact was made.^[5][46] The lifespan in the wild is not known; however, in captivity the species can live for over 15 years, and possibly up to 30 years in some cases.^[4]

Status

Verreaux's eagle-owl is a seldom-encountered species, occurring at low densities and needing large territories for hunting and breeding purposes. The threats faced by this species are sadly typical of many large birds of prey from around the world. Not infrequently, they are locally rare due to persecution.^[8][11] The normal cause of persecution is their possible status as predators of small domestic stock, though this is certain to be rare, at least in areas with substantial wild prey populations.^[8][154] An additional threat is the residual effects of pesticides, as poison (usually through rodenticide or poisoned carcasses left out for scavengers such as jackals) consumed through prey may badly affect them.^[4][155] They may be killed by flying into novel man-made objects, including wires and massive dams along reservoirs.^{[156][157][158]}

Habitat destruction can also affect them, as they require ample trees with large bird nests in order to take residence in a given area.^[8][159] In some areas, however, they've been shown to be able to nest in peri-urban or suburban areas, showing greater adaptability to human-based land changes than many other large birds of prey.^[104][128] In Eswatini, the species is considered Near Threatened and the species has been recommended for threatened status in southern Africa overall.^{[160][161][162]} In west Africa and central Africa, the habitat is often marginal for this species, the distribution is sporadic and thus this eagle-owl is only encountered either uncommonly or rarely.^[1][37][82] The greatest regional stronghold for Verreaux's eagle-owls is seemingly east Africa, in countries such as Kenya, which may have numbers comparable to pre-colonial times.^[5][82] At the species level, they are widespread and currently not considered to be threatened with extinction.^[1][4]

References

• Owls of the World by Konig, Weick & Becking. Yale University Press (2009), ISBN 9780300142273

Retrieved from "https://en.wikipedia.org/w/index.php?title=Verreaux%27s_eagle-owl&oldid=1158367511"

El búho lechoso o búho de Verreaux (Bubo lacteus) es una especie de búho perteneciente a la familia Strigidae que vive en el África subsahariana y la mayor especie de búho de África.

Taxonomía

Se han realizado estudios para intentar encontrar relaciones genéticas entre el búho lechoso y las otras especies dentro del género Bubo. Estas investigaciones no reflejaron ningún resultado claro, pero parece ser que los búhos vivos con un parentesco más cercano a esta especie son el búho de Nepal (Bubo nipalensis), el búho malayo (Bubo sumatranus) y el búho pescador de Ceilán (Ketupa zeylonensis). Los búhos fósiles del Plioceno, con claras similitudes basadas en características osteólogicas al moderno búho lechoso, indican que el búho lechoso descendió de ancestros ligeramente más pequeños que aumentaron en tamaño a medida que se diversificaron de especies relacionadas.

No hay subespecies reconocidas del búho lechoso debido a que las variaciones en la especie son mínimas a pesar de su amplísima área de distribución. Según parece, las aves en la parte sur del área de distribución son un poco más grandes que la media, pero estas diferencias de tamaño son bastante sutiles.

Descripción

El búho lechoso es la especie de búho más grande África. Se trata de un animal grande y poderoso que ocupa el cuarto lugar como búho más pesado (tras el Búho de blakiston, el Búho real y el Búho pescador leonado); además del cuarto lugar como búho de mayor longitud (tras el Cárabo lapo, el Búho mancha y el Búho real).

Tiene una longitud total de 58 a 66 cm. La envergadura de las alas puedes ser de entre 140 y 164 cm. Las hembras son casi siempre más grandes que los machos, destacando el búho lechoso por ser una de las especies de búho con mayor dimorfismo sexual pues la hembra puede llegar a tener un 35% de peso más que el macho. Los machos pueden pensar entre 1,6 y 2 kg mientras que las hembras llegan a pesar entre 2,5 y 3,1 kg.

En general, el búho lechoso presenta un colorido gris pálido bastante uniforme con vermiculaciones finas (rayas onduladas) de color marrón claro en la parte inferior. La espalda es de un color marrón con algunas manchas blancas en el hombro. El disco facial es más pálido que el resto del cuerpo y esta enmarcado con unos bordes negros a cada lado. Una característica que ayuda a identifica al búho lechoso inmediatamente son sus párpados rosados. Se desconoce el propósito ecológico de estos coloridos párpados. Algunos autores han sugerido que pueden ser para reemplazar la carencia de los llamativos ojos amarillos o anaranjados, que tienen otras especies, y que tiene un papel importante para lucirse en el apareamiento. Sus ojos son de color marrón oscuro y tiene dos penachos de plumas, que se asemejan a orejas, encima de la cabeza. Estos penachos son más discretos en esta especie y serán difíciles de distinguir si los mantiene laxos.

Distribución y hábitat

El búho lechoso se encuentra en la mayor parte del África subsahariana, aunque está ausente en las selvas tropicales profundas. La especie se encuentra en mayores densidades en África oriental y meridional. Existen poblaciones aisladas en Nigeria, en Mali y en la costa sur de Sudáfrica.

Esta especie habita principalmente sabanas con árboles dispersos y vegetación espinosa. Los búhos lechosos viven en regiones más bien secas, algunas bordean áreas áridas como el semidesierto. También abarcan bosques ribereños adyacentes a la sabana y pequeños bosques semiabiertos rodeados de campo abierto, aunque es menos probable que habiten hábitats muy boscosos. En el sur de África se encuentran con no poca frecuencia alrededor de las llanuras de inundación y las marismas que pueden proporcionar lugares de anidación adecuados. Puede vivir hasta 3.000 m de altura, sin embargo, solo habitan esporádicamente áreas rocosas y, por lo tanto, son muy escasos en las regiones montañosas. Históricamente, la especie estuvo ausente en el desierto de Kalahari pero la introducción por el hombre de árboles como coníferas, eucaliptos y acacias, áreas de riego y especies de presas estrechamente ligadas al hombre les ha permitido ocupar de manera irregular. esta región.

Comportamiento

Los búhos lechosos son aves nocturnas que se posan durante el día en los árboles, prefiriéndo las grandes ramas horizontales sombreadas de los árboles altos y viejos (generalmente acacias). A pesar de que prefiere un follaje denso para descansar; a veces, al terminar una noche de caza puede posarse en algún lugar más expuesto en su área de caza. Tienen un sueño bastante ligero y se despertarán muy rápido para defenderse de ataques durante el día. Los grupos familiares que consisten en parejas reproductoras y sus descendientes, que pueden incluir búhos de hasta tres años antes, lo que es excepcional para cualquier tipo de especie de búho. Durante los días extremadamente calurosos, esta especie puede beber y darse baños en aguas poco profundas, pero generalmente bebe durante la noche. Cada pareja reproductora del búho lechoso defiende un territorio y estos pueden ser extremadamente grandes, con un tamaño de hasta 7,000 ha.

Alimento

Este búho es un depredador que se encuentra en la parte superior de la cadena alimentaria o cerca de él, y los adultos sanos normalmente no tienen depredadores naturales. Muchos aspectos de su comportamiento de caza entran dentro de los típicos de los miembros del género Bubo. Esta especie caza predominantemente al anochecer. Los búhos lechosos cazan principalmente lanzándose sobre su presa desde una percha donde se encuentra posado. Sin embargo, también se sabe que pueden cazar durante el vuelo insectos, pájaros o murciélagos. En ocasiones, cazan volando a baja altura sobre un arbusto para atrapar a sus presas por sorpresa o vuelan a través del denso follaje o a través de los bosques para atrapar un galago u otra presa arbórea. A veces también vadean en aguas poco profundas para atrapar peces.

Se trata de una especie oportunista que cazará cualquier animal que pueda atrapar entre sus garras, aunque se sabe que la mayor parte de su dieta consiste en mamíferos. El búho lechoso está especializado en la caza de erizos, siendo la única especie en África que caza a estos animales de forma habitual. En general, la dieta de este búho es muy variada y se sabe que prefiere cazar piezas grandes que le aporten mayor alimento en una sola captura, que realizar muchas capturas de animales pequeños. Además de los erizos, entre los mamíferos que caza se encuentran: ratas-topo, roedores, ardillas, liebres, crías de monos, murciélagos, musarañas, damanes y mangostas. También caza cualquier tipo de ave, reptiles, anfibios, peces, insectos y otros artrópodos. Al ser una animal de hábitos nocturnos sus presas serán también en su mayoría aquellas especies que son más activas por la noche.

Reproducción

El período de reproducción se sitúa entre febrero y septiembre.^[2]​ Se cree que la época de cría está relacionada con la llegada de la estación seca por lo que irá variando según la zona de su amplio rango. Es una especie monógama que probablemente se apareen de por vida. Realizará un cortejo para encontrar pareja o para reforzar los lazos con la pareja existente antes de la cópula. Durante el cortejo se inclinarán el uno ante el otro, abrirán sus alas y se arreglarán las plumas entre ellos, tomando el macho una parte más activa en el ritual. Son aves territoriales que defenderán sus dominios que puede llegar hasta las 7000 ha. Es raro que esta especie construya sus propios nidos, normalmente, reutiliza los nidos construidos por aves de otras especies. En general, estos nidos ya se encuentran abandonados cuando el búho lechoso los reclama pero, a veces, están ocupados y el búho procederá a echar a sus ocupantes que incluso pueden convertirse en su presa.

De media la hembra pondrá dos huevos, con un intervalo de hasta una semana entre ellos, siendo mayor el primero que el segundo. La incubación, realizada por la hembra, durará hasta 40 días, siendo uno de los mayores periodos de incubación entre las especies del género Bubo. Durante la incubación y 20 días después de la eclosión la hembra permanece en el nido y el macho es quien le proporciona el alimento. Ambos padres defenderán ferozmente al nido y sus ocupantes de cualquier intruso que se acerque demasiado. Los polluelos crecen exponencialmente en sus 5 primeros días. El polluelo del primer huevo, al nacer primero, siempre será de mayor tamaño que el segundo y es habitual que este segundo polluelo termine muriendo (el polluelo primogénito acapara más comida e incluso puede llegar a atacar y matar a su hermano). Las crías nacen cubiertas de un plumón blanquecino y los párpados rosados son ya visibles a la semana de vida.

A los dos meses de vida las crías empiezan a explorar los alrededores del nido y necesitarán entre dos semanas y un mes más para empezar a volar moderadamente. Durante este periodo son muy vulnerables y serán objeto de acoso por otras aves que generalmente son presas habituales de esta especie. Para defenderse los polluelos suelen esconderse entre el ramaje de los árboles, e incluso, si consiguen tirarlos al suelo se harán los muertos hasta que el peligro haya pasado. A los 5 meses ya son capaces de cazar y alimentarse por sí mismos, aunque muchos de ellos permanecen con sus padres hasta varios años después, formando pequeños grupos familiares y ayudando en la crianza de las crías de nidadas posteriores.

La madurez sexual se alcanza entre los 3 y 4 años. Los búhos lechosos suelen reproducirse anualmente pero si el alimento es escaso puede que pasen algunos años sin hacerlo. La esperanza de vida de esta especie en libertad es desconocida pero los especímenes en cautiverio alcanzan los 15 años, incluso hay algunos casos que han llegado a los 30.

Conservación

El búho lechoso es una especie rara de observar que se encuentra en bajas densidades y que necesita amplios territorios para vivir. Los peligros a los que se enfrenta suelen ser compartidos por la mayoría de las aves rapaces. A veces, son perseguidos por cazar animales domésticos aunque esto no suele ser habitual y será un síntoma de que la caza de animales salvajes escasea. También puede ser envenenados por pesticidas y raticidas que ingieren a través de sus presas. La destrucción de su hábitat también les afecta, pues requiere árboles grandes donde anidar, aunque muestra mayor adaptabilidad a la expansión humana que otras especies. A pesar de que en algunas zonas de su rango escasee, a nivel especie sigue siendo un animal común con una población estable por lo que es catalogada por la UICN como especie de preocupación menor.

Referencias

Bubo lacteus Bubo generoko animalia da. Hegaztien barruko Strigidae familian sailkatua dago.

Erreferentziak

• World Bird Names

Ikus, gainera

• Bubo
• Strigidae

Savannihuuhkaja (Bubo lacteus) on Afrikassa elävä huuhkajiin kuuluva pöllölintu. Se on maailman suurimpia pöllöjä.

Koko ja ulkonäkö

Savannihuuhkaja on Saharan eteläpuolisen Afrikan suurin pöllölaji. Sen pituus on 60–66 senttiä^[2], ja siipiväli keskimäärin 140 senttiä. Naaraat painavat 2,5–3,1 kiloa, koiraat 1,6–1,9 kiloa. Höyhenpeite on harmaanruskea. Selässä kulkee valkoisia aaltomaisia viiruja. Vaaleampi vatsapuoli on selkäpuolta tiheäviiruisempi, ja viiruja on myös siivissä. Vaaleassa naamassa on musta reunus.^[3] Lajille ovat tunnusomaisia myös pitkät höyhentupsut ja punaiset silmäluomet.^[2] Silmät näyttävät kaukaa katsottuna tummilta, mutta ovat oikeasti oranssit tai keltaiset.^[4] Koiraat ovat naaraita selvästi pienempiä, eikä niiden "naamalevy" ole yhtä pyöreä kuin naaraiden. Nuoret linnut eroavat aikuisista yksilöistä siinä, että niiden ruumiissa on noenvärisiä juovia ja päässä on valkoisia laikkuja.^[3] Savannihuuhkajan kynnet ja jalat ovat suuret ja vahvat.^[4]

Levinneisyys ja elinympäristö

Savannihuuhkaja elää Saharan eteläpuolisessa Afrikassa. Sen levinneisyys ulottuu pohjoisessa Pohjois-Etiopiasta ja Somaliasta etelään aina Etelä-Afrikkaan saakka. Useita sirpaloituneita populaatioita elää myös ympäri Länsi-Afrikkaa, jossa sitä tavataan muun muassa Senegalissa, Kamerunissa ja Malissa. Lajin uskotaan eläneen myös Lesothossa, mutta on jo hävinnyt maasta.^[3] Se puuttuu myös sademetsistä ja Namibin aavikolta.^[5]

Savannihuuhkajia tavataan merenpinnan tasolta jopa 3000 metrin korkeuteen. Se elää metsiköissä, kuivilla savanneilla, puu- ja pensassavanneilla, avoimilla ruohotasangoilla, maatalousalueilla, jokivarsimetsissä, soilla ja tulvatasangoilla.^[3][2] Savannihuuhkaja pärjää myös kaupungeissa mikäli puita on riittävästi.^[6] Laji elää usein vesistöjen lähellä, mutta karuja aavikoita ja tiheitä metsiä se karttaa.^[3][2]

Elintavat

Savannihuuhkaja on yöaktiivinen paikkalintu, joka liikkuu yksin tai pareittain. Sitä näkee melko usein päivälläkin puiden oksilla ja kallionkielekkeillä, etenkin vesistöjen lähellä. Se on päivällä hiljainen, mutta päästää yöllä syvää ja käheää, osittain murahtelevaakin hryu hryu hooo huhuilua.^[2][4] Huhuilu voi kuulua viiden kilometrin päähän.^[7]

Ravinto

Savannihuuhkaja on saalistustavoiltaan opportunisti.^[6] Se saaliseläimiä ovat muun muassa jänikset, tamaanit, jyrsijät, kääpiömangustit, vihermarakatit, kalat, konnat, käärmeet, hyönteiset, varaanit ja muut lintulajit aina flamingoihin, sihteereihin, haikaroihin ja petolintuihin saakka. Myös raadot kelpaavat.^[6][2] Kaupungeissa lajin ravintoa ovat kyyhkyt ja rotat. Savannihuuhkaja kuuluu niihin harvoihin petolintuihin, jotka saalistavat siilejä.^[6] Siilit ovat aikuisten lintujen suosimaa ravintoa. Sen tiedetään syövän myös pienempiä pöllöjä^[6] ja jopa muita huuhkajia (Bubo). Savannihuuhkaja paikantaa saaliinsa erinomaisen näkönsä avulla sopivalta tähystyspaikalla. Havaittuaan saaliin se lipuu hiljaa kohti maata ja nappaa saaliin vahvoihin kynsiinsä. Se pystyy myös sieppaamaan kaloja upottamalla jalkansa veteen, ja on kyllin ketterä nappaamaan lintuja ilmasta.^[3]

Lisääntyminen

Savannihuuhkajat pesivät yleensä muiden lintujen kuten korppikotkien, vasarapäähaikaroiden tai sihteerien vanhoissa ja isoissa risupesissä. Ne pesivät satunnaisesti myös puunonkaloissa ja köynnösten tai orkideoiden muodostamissa ryteiköissä.^[3][2] Lisääntymisaika vaihtelee eri alueilla,^[3] mutta yleensä se on maalis-syyskuussa.^[5] Naaras munii noin päivän välein yhteensä kaksi munaa, joita se hautoo ilman koirasta noin 38 päivää.^[3] Koiras ruokkii kumppaniaan haudonnan ajan.^[6] Toinen poikasista kuolee yleensä kahden viikon sisällä kuoriutumisesta.^[3] Henkiinjäänyt poikanen on yleensä munittu aikaisemmin kuin sisarensa ja luonnollisesti se myös kuoriutuu aiemmin. Nuoremmalla on mahdollisuus selvitä vain, jos toiselle munalle käy jotain tai ruokaa on runsaasti.^[6] Poikanen lähtee pesästä noin yhdeksän viikon ikäisenä, mutta on riippuvainen vanhemmistaan vielä puolivuotiaaksi asti.^[3] Se pysyttelee emolintujen luona kaksi vuotta ennen kuin itsenäistyy kokonaan.^[2] Edellisvuoden poikaset saattavat jopa auttaa vanhempiaan seuraavan poikueen hoidossa.^[6] Savannihuuhkajat lisääntyvät hitaasti. Osa huuhkajapareista pesii vuosittain, mutta jotkin parit pesivät muita harvemmin.^[3]

Lähteet

Bubo lacteus

Le Grand-duc de Verreaux^[a] (Bubo lacteus) est une espèce de rapaces nocturnes de l'Afrique subsaharienne de la famille des Strigidae.

C'est le troisième plus grand hibou au monde après le Kétoupa de Blakiston et le Hibou grand-duc, et le plus grand hibou d'Afrique. Il a été nommé en hommage au botaniste et ornithologue français Jules Verreaux^[4].

Description

Ce hibou atteint une longueur de 65 centimètres, pour une envergure de 1,40 mètres et un poids allant de 1 615 à 3 115 grammes, les femelles étant plus grandes que les mâles, comme chez la plupart des rapaces nocturnes^[4]. En apparence, il se distingue par un disque facial blanchâtre ovale avec une bordure noire, des yeux brun foncé, des paupières roses et deux touffes de plumes sur leurs oreilles. Le manteau et le dos sont brun-gris clair, avec des bandes blanches en quantité variable selon les individus. Les parties inférieures sont gris clair, finement vermiculées de clair et de foncé et plus sombres au niveau du cou.

Écologie et comportement

Le grand-duc de Verreaux est un oiseau nocturne qui se repose le jour dans de grands arbres. Il dort peu et se réveille très rapidement pour se défendre contre une attaque en plein jour.

Alimentation

Ce hibou chasse à l'affut, depuis un perchoir, en début de soirée. Il a une alimentation variée, il se nourrit de mammifères de taille moyenne (lièvres, mangoustes...) et d'oiseaux. Il mange aussi occasionnellement des poissons, grenouilles, reptiles ainsi que des arthropodes^[5]. C'est l'un des rares oiseaux à se nourrir de hérissons, dont il parvient à enlever les piquants.

Reproduction

La reproduction a lieu de mars à septembre. Cette espèce ne construit pas de nids, mais récupère des nids abandonnés d'autres oiseaux, se sert par exemple des nids du républicain social comme plateforme^[6] ou utilise des trous dans de grands arbres^[4]. La femelle pond deux œufs et les couve pendant trente-huit jours. Elle reste sur le nid pendant toute la période d'incubation tandis que le mâle chasse la nourriture pour les deux. Le premier œuf à éclore détermine le premier à être nourri, et si la nourriture n'est pas abondante, seul le premier oisillon éclos sera nourri. Si la nourriture est abondante, les deux le seront. Les oisillons sont prêts à quitter le nid à neuf semaines, mais restent avec leurs parents pour un maximum de trois mois supplémentaires.

Galerie

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• Bubo lacteus (Parc national Kruger, Afrique du Sud)

Notes et références

Notes

Références

Voir aussi

Références taxonomiques

• (en) Référence Congrès ornithologique international : (consulté le 21 mai 2015)
• (fr+en) Référence Avibase : Bubo lacteus (+ répartition) (consulté le 1^er juillet 2015)
• (en) Référence Zoonomen Nomenclature Resource (Alan P. Peterson) : Bubo lacteus dans Strigiformes
• (en) Référence UICN : espèce Bubo lacteus Temminck, 1820 (consulté le 1^er juillet 2015)
• (fr) Référence CITES : taxon Bubo lacteus (sur le site du ministère français de l'Écologie) (consulté le 1^er juillet 2015)
• (en) Référence CITES : espèce Bubo lacteus Temminck, 1820 (+ répartition sur Species+) (consulté le 1^er juillet 2015)
• (en) Référence NCBI : Bubo lacteus (taxons inclus)

Il gufo latteo o gufo reale di Verreaux (Bubo lacteus (Temminck, 1820)) è un grande uccello appartenente alla famiglia Strigidi, diffuso in Africa.^[2]

Descrizione

Nonostante sia più piccolo del Gufo reale e del Gufo comune, presenta grandi dimensioni e una lunghezza di 53-61 cm. Il piumaggio è di color grigio bruno uniforme, più chiaro e finemente barrato di nero sulle parti inferiori. Due strisce scure delimitano il disco facciale di colore bianco sporco. L'iride è di color bruno nero. L'apertura alare è di 150 cm e la femmina è di poco più grande del maschio.

Distribuzione e habitat

Diffuso in Africa centro-meridionale, vive a ovest fino alla Nigeria, a nord fino al Sudan, a est fino all'Etiopia, a sud fino al Sudafrica.

Diffuso in foreste e praterie, si adatta anche al deserto. Gli ambienti abitati con maggiore frequenza sono le foreste lungo i fiumi, anche quelle intricate in cui il gufo reale non si spinge. Ivi il gufo latteo trova molto cibo e riparo.

Biologia

Riproduzione

Il nido è posto nelle cavità di grandi alberi, ma più spesso nel nido abbandonato da grandi rapaci. Sono deposte 1-3 uova, più spesso 2, covate per qualche decina di giorni da entrambi i sessi. I nidacei, una volta in grado di volare, stanno coi genitori ancora per qualche settimana. Gli adulti inscenano delle parate ostentative figurandosi feriti se un predatore si avvicina al nido.

Alimentazione

Il gufo latteo si nutre di prede di notevoli dimensioni, catturate sul terreno nelle radure e al limitare dei boschi: lepri, conigli, procavie, uccelli delle dimensioni di un francolino e, in seconda misura, di serpenti, pipistrelli e grandi insetti.

Note

Bibliografia

• del Hoyo, J.; Elliott, A.; Sargatal, J., Handbook of the Birds of the World, vol. 5: Barn-owls to Hummingbirds, Barcellona, Lynx Edicions, 1999.

Vogels

Verreaux' oehoe (Bubo lacteus) (ook wel melkwitte ooruil) is een soort oehoe die voorkomt in Sub-Saharisch Afrika.

Kenmerken

Volwassen dieren meten ruim 60 tot 65 centimeter, wat maakt dat dit de grootste Afrikaanse uil is. De uil is onmiskenbaar. Deze oehoe is grijsbruin van boven en is van onder melkwit, met daarin een fijne streping. Opvallend zijn de rozekleurige oogleden.^[2]

Leefwijze

Deze uil is een schemer- en nachtactieve vogel. Zijn prooi bestaat in hoofdzaak uit slangen en hagedissen. Hij broedt in de holtes van dikke bomen (baobabs) of ongebruikte nesten van de palmgier.^[2]

Verspreiding en leefgebied

Hij komt voor in grote delen van Afrika ten zuiden van de Sahara en is met name aan te treffen in streken waar veel acacia's groeien. Het is een vogel van half open landschappen waarin plaatselijk grote, oude bomen staan zoals in bossavannes.^[2]

Status

Verreaux' oehoe heeft een groot verspreidingsgebied en daardoor is de kans op de status kwetsbaar (voor uitsterven) gering. De grootte van de populatie is niet gekwantificeerd. Er is geen aanleiding te veronderstellen dat de soort in aantal achteruit gaat. Om deze redenen staat Verreaux' oehoe als niet bedreigd op de Rode Lijst van de IUCN.^[1]

Bronnen, noten en/of referenties

Gråhubro (Nyctaetus lacteus) er en ugle i gruppen Bubo. Selv om den er blitt mer sjelden, er den ikke vurdert som truet art. I Afrika vurderer man gråhubro som en fugl som bringer ulykke. Om et menneske blir angrepet av fuglen, mener man at det vil dø etter kort tid.

Beskrivelse

Denne uglen er en av de største av uglene i verden. Den er 66 til 71 cm høy og har et vingespenn på 200 cm. Vekten er omkring fire kilo. Å se til er de i ansiktet som en hvitaktig oval plate med en svart kant. De har rosa øyelokk, orange øyne og to fjærdusker på ørene. Fjærene er mørkebrune over og lysegrå under.

Habitat

Gråhubro finnes i Afrika sør for Sahara. Den liker seg langs skogsbekker og elver, sjelden over 2000 meter. De er nattjagere og sitter i høye trær om dagen. De sover lett og våkner svært fort for å forsvare seg mot angrep i dagslys.

Jakt skjer tidlig om kvelden. Voksne gråhubroer jakter på harer, mungoer og mye annet småvilt og er en av få fugler som tar piggsvin. Nær byer kan de også ta rotter og duer.

Levevis

Gråhubro bygger reir i mars-april, i tørketiden i Afrika. Den tar gjerne i bruk hule trær eller et gammelt reir fra en annen fugl. Hunnen legger to egg og ruger i 38 dager. Hannen jakter på mat for begge. Den første ungen som kommer ut av egget, er den som først får mat, og om det ikke er mye mat, blir det bare den som får noe. Om det er rikelig, vil begge ungleungene bli foret. De kan forlate reiret etter ni uker, men mange vil holde seg med foreldrene i opp til tre måneder, helt til september.

Referanser

Eksterne lenker

• (en) Gråhubro i Encyclopedia of Life
• (en) Gråhubro i Global Biodiversity Information Facility
• (en) Gråhubro hos NCBI
• (en) Gråhubro hos ITIS
• (en) Kategori:Bubo lacteus – bilder, video eller lyd på Wikimedia Commons
• (en) Bubo lacteus – galleri av bilder, video eller lyd på Wikimedia Commons
• Bubo lacteus – detaljert informasjon på Wikispecies
• Gråhubro hos IUCN Rødliste
• Sense of Wilderness
• Eagle Owls
• Bubo lacteus
• Stort bilde som viser røde øyelokk
• Gråhubro - videoer på Internet Bird Collection

Multimedia w Wikimedia Commons

Puchacz mleczny (Bubo lacteus) – gatunek dużego ptaka z rodziny puszczykowatych. Występuje w nieregularnym rozmieszczeniu w Afryce subsaharyjskiej. Nie jest zagrożony wyginięciem.

Taksonomia

Po raz pierwszy gatunek opisał Coenraad Jacob Temminck w 1820. Do opisu była dołączona tablica barwna opatrzona numerem 4. Holotyp pochodził z Senegalu i przechowywany był w zbiorach de Laugiera. Autor nadał nowemu gatunkowi nazwę Strix lactea^[3]. Obecnie (2018) Międzynarodowy Komitet Ornitologiczny umieszcza puchacza mlecznego w rodzaju Bubo^[4], nie są jednak znane jego dokładne pokrewieństwa w obrębie rodzaju^[5]. Gatunek monotypowy^[4][5]. Puchacz mleczny był obiektem badań genetycznych. W jednym z nich badano zawartość DNA w komórce, która u przedstawiciela tego gatunku wyniosła 4,56 pg^[6]. W 1993 opublikowano wyniki badań nad kariotypem wybranych gatunków ptaków. W przypadku puchacza mlecznego uzyskano jednak niedokładny wynik (2n=80–84)^[7].

Morfologia

Długość ciała wynosi 60–65 cm. Masa ciała samca 1615–1960 g, samicy 2475–3115 g. Rozpiętość skrzydeł 140–164 cm^[5]. Puchacz mleczny jest największą sową Afryki. „Uszy” (pęczki piór na głowie) są krótkie, rozczochrane^[8]. W upierzeniu nie występuje dymorfizm płciowy, samice są jednak przeciętnie większe i cięższe od samców. Szlara jest brudnobiała, szeroko czarno obwiedziona. Pióra szczeciniaste wokół dzioba czarniawe. Wierzch ciała jasny, szarobrązowy, o „mlecznym” wyglądzie, ozdobiony białawymi prążkami ułożonymi w marmurkowy wzór. Podobny występuje na „uszach”, jednak w ciemniejszym odcieniu. Barkówki zajęte są przez duże, białe plamy, tworzące biały pas biegnący przez ramię. Lotki i sterówki pokryte są na zmianę ciemnymi i jasnymi pasami. Gardło porośnięte białymi piórami, szczególnie dobrze widocznymi podczas nawoływania. Spód ciała jaśniejszy od wierzchu, szarobrązowy, upstrzony ciemnymi i jasnymi prążkami ułożonymi w nieregularny sposób. Palce częściowo opierzone. Tęczówka ciemna, oko obwiedzione przez ciemne krawędzie powiek. Górne są nagie i różowe. Woskówka niebieskoszara, dziób jasny, kremowy, z szarą nasadą. Nagie części palców mają barwę szarawą, pazury natomiast brązową (z wyjątkiem czarnych zakończeń)^[9].

Zasięg występowania

Zasięg występowania puchaczy mlecznych rozciąga się w Afryce subsaharyhjskiej. BirdLife International szacuje go na 25,5 mln km²^[10]. Obejmuje obszar od południowej Mauretanii i centralnego Mali na wschód po centralny Sudan, Erytreę i Somalię i dalej na południe po RPA^[5]. W południowej części Afryki są lokalnie pospolite w północnej i centralnej Namibii, Botswanie, Zimbabwe, Mozambiku i północnym RPA^[11].

Ekologia i zachowanie

Środowiskiem życia puchaczy mlecznych są suche sawanny z porozrzucanymi drzewami i ciernistymi krzewami, nadrzeczne lasy z przyległą sawanną, zadrzewienia i niewielkie, półotwarte lasy na otwartych terenach. Najpospoliciej zamieszkują otwarte sawanny i półpustynie, nieczęste są w bujnie rozwiniętych lasach, zaś w tych gęstych nie występują wcale. We wschodniej Afryce to typowe ptaki sawanny z ciernistą roślinnością. Odnotowywane były od poziomu morza do 3000 m n.p.m. Przeważnie aktywne są nocą, jednak wypatrzywszy odpowiednią zdobycz mogą podjąć się polowania i o innej porze. Za dnia odpoczywają na dużych, poziomych gałęziach zazwyczaj dobrze zacienionych i ukrytych. Młode osobniki mogą przesiadywać blisko siebie. Ptaki połączone w pary często podczas odpoczynku wzajemnie się pielęgnują. Puchacze mleczne regularnie kąpią się w kroplach deszczu lub w płytkiej wodzie. Podczas upałów trzepoczą piórami na gardle, by się schłodzić^[9]. Nie ma pewnych danych o wędrówkach czy lokalnych migracjach o charakterze nomadycznym. Za występowaniem nomadyzmu u ptaków tego gatunku przemawiają jednak stwierdzenia z miejsc, gdzie te zazwyczaj nie występują czy niezajmowanie tych samych terytoriów w kolejnych latach^[12]. Wśród młodych występuje dyspersja polęgowa^[5].

Pożywieniem puchaczy mlecznych są głównie średniej wielkości ssaki i duże ptaki. Zjadają również padlinę. Lokalnie ich preferowanym pokarmem są jeże. Zdzierają ich kolczastą skórę i wyrzucają, podobnie jak to czynią puchacze (B. bubo). Ze ssaków jedzą również młode małpy, warchlaki guźców (Phacochoerus africanus), postrzałki (Pedetes), zające (Lepus), żenety (Genetta), góralkowce (Hyracoidea), świstaki (Marmotini), rudawkowate (Pteropodidae), szczury (Rattus) i myszy (Mus). Łapane przez puchacze mleczne ptaki osiągają różne rozmiary, od astryldów (Estrildidae) i wikłaczowatych (Ploceidae) po czaplowate (Ardeidae), sekretarze (Sagittarius serpentarius), pisklęta sępów, frankoliny, kaczki (żółtodziobe, Anas undulata i moręgówki, A. sparsa^[11]) i młode żurawie. Dodatkowo zjadają również gady, płazy bezogonowe, ryby i stawonogi – w tym dwuparce oraz skorpiony i inne pajęczaki. Są w stanie podnieść zdobycz ważącą do 1,8 kg (jak mangustowate). Dziennie spożywają ilość pokarmu odpowiadającą 5% swojej masy ciała. Polując szybko szybują w dół z gałęzi. Łapią również owady w locie lub wpadają w listowie, by łapać odpoczywające ptaki lub galagowate. Rzadziej pokarmu szukają w płytkiej wodzie, w krzewach czy na ziemi^[9].

Lęgi

Okres składania jaj trwa w większości obszaru występowania od marca do września, głównie od czerwca do sierpnia. W zachodniej części zasięgu okres ten przypada na styczeń–marzec, w północno-wschodniej natomiast na październik–styczeń^[5]. W północnym RPA zniesienia przypadają na okres od czerwca do września^[12]. Niekiedy lęgi wyprowadzają tylko raz na 2 lub 3 lata, być może z powodu ograniczonego dostępu do pożywienia. Puchacze mleczne korzystają głównie z opuszczonych gniazd z gałęzi służących wcześniej między innymi sępom, sekretarzom, warugom (Scopus umbretta), krukowatym^[9], tkaczom (Philetairus socius) i bawolikom czerwonodziobym (Bubalornis niger)^[12][11]. Od czasu do czasu używają dziupli w starych drzewach^[9] lub gniazd w plątaninie pnączy^[11]. Przeważnie zniesienie liczy 2 białe jaja o średnich wymiarach 62,6 × 51,4 mm i masie wynoszącej 93,1–101,6 g). Inkubacja trwa 32–39 dni^[9].

Młode wykluwają się w tygodniowym odstępie, ważą po wykluciu 60–70 g. Początkowo całkowicie pokrywa je kremowy puch, następnie wyrasta puch pośredni (mesoptile), jasnoszary z nieregularnymi prążkami i ciemnymi paskami. Młode puchacze mleczne mają mniej widoczną ciemną krawędź szlary. Zazwyczaj młodsze z piskląt umiera w ciągu pierwszych dwóch tygodni życia, nie jest wiadome, czy wskutek kanibalizmu, czy zagłodzenia. Przez pierwsze dwa tygodnie życia samica strzeże piskląt w gnieździe. Później obydwa ptaki z pary przebywają już na zewnątrz dziupli, ostrzegają potomstwo chrząkającymi głosami w razie zbliżenia się drapieżnika. Młode opuszczają gniazdo po 62–63 dniach życia. Są zdolne do lotu dwa tygodnie po opierzeniu. Przebywają głównie w ukryciu wśród drzew lub krzewów i przed ukończeniem trzech miesięcy życia wykazują niewiele aktywności. Zaskoczone podczas siedzenia na ziemi udają martwe i mogą zostać złapane bez problemu. Pięciomiesięczne puchacze mleczne potrafią już łapać zdobycz samodzielnie. Czasami pozostają z rodzicami przez dwa lata, zanim zaczną się rozmnażać. Dojrzałość płciową osiągają w wieku 3–4 lat^[9].

Status

IUCN uznaje puchacza mlecznego za gatunek najmniejszej troski (LC, Least Concern) nieprzerwanie od 1988 (stan w 2018). BirdLife International ocenia trend populacji jako stabilny^[10]. Według danych z początku XXI wieku w południowej części Afryki puchacze mleczne częściej stwierdzane były na obszarach chronionych, jak Transgraniczny Park Narodowy Kgalagadi i Park Narodowy Etoszy. Wskazuje to na konieczność ochrony tych ptaków^[12].

Przypisy

O Bufo-de-verraux (Bubo lacteus) é uma espécie de ave estrigiforme pertencente à família Strigidae. Com uma envergadura de cerca de 2 m, o bufo-de-verraux é um dos maiores membros do seu grupo.^[2]

O bufo-de-verraux habita a África sub-sahariana. Alimenta-se de lebres, coelhos, mangustos, e outros mamíferos de pequeno porte. Como todas as outras corujas e mochos, o bufo-de-verraux é uma ave de hábitos noturnos.

Referências

Mjölkuv^[2] (Bubo lacteus) är en fågel i familjen ugglor inom ordningen ugglefåglar.^[3] Den förekommer på savann och i skogsmarker i Afrika, söder om Sahara.^[3] IUCN kategoriserar arten som livskraftig.^[1]

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Noter

1. ^ [a b] Birdlife International 2012 Bubo lacteus Från: IUCN 2015. IUCN Red List of Threatened Species. Version 2015.4 www.iucnredlist.org. Läst 2016-02-01.
2. ^ Sveriges ornitologiska förening (2016) Officiella listan över svenska namn på världens fågelarter Arkiverad 18 oktober 2014 hämtat från the Wayback Machine., läst 2016-02-10
3. ^ [a b] Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2015) The eBird/Clements checklist of birds of the world: Version 2015 http://www.birds.cornell.edu/clementschecklist/download, läst 2016-02-11

Externa länkar

• Wikimedia Commons har media som rör mjölkuv.
  Bilder & media
• Wikispecies har information om Bubo lacteus.
  Artförteckning

• 1 Опис
• 2 Спосіб життя
• 3 Розмноження
• 4 Примітки

1. ↑ Фесенко Г. В. Вітчизняна номенклатура птахів світу. — Кривий Ріг : ДІОНАТ, 2018. — 580 с. — ISBN 978-617-7553-34-1.
2. ↑ http://www.apus.ru/site.xp/049048052051124051056053053.html

Cú đại bàng Verreaux (Bubo lacteus), cũng được gọi là Cú đại bàng sữa hoặc Cú đại bàng lớn là một thành viên trong Họ Cú mèo và là loài cú châu Phi lớn nhất. Loài này cũng là loài cú có cân nặng thứ ba trên thế giới, sau Dù dì Blakiston và Cú đại bàng Á Âu và là loài cú dài thứ tư, sau hai loài kể trên và Hù xám lớn.^[2][3]

Tên gọi của nó nhằm kỷ niệm nhà tự nhiên học người Pháp Jules Verreaux.^[4]

Miêu tả

Cú đại bàng Verreaux loài cú rất lớn và mạnh mẽ. Con trống và con mái có vẻ bề ngoài tương tự nhau, tuy rằng con mái có kích thước lớn hơn và nặng hơn. Mặt dạng đĩa màu trắng xỉn, với viền đen bao quanh. Túm lông tai điển hình ngắn và bù xù. Mắt màu nâu sẫm, phía trên mi mắt màu hồng, lông mi màu vàng nâu. Da gốc mỏ màu xám xanh, mỏ màu kem nhạt, gốc mỏ màu xám Lông xung quanh mỏ hơi sẫm hơn. Phần trên lưng màu nâu xám nhạt, ngả màu sữa, với những đường vân mịn màu trắng, và một loạt đốm trắng ở vai. Phần dưới bụng màu nâu xám nhạt hơn, với những đường vân rất mịn, dày đặc. Cổ họng trắng, nổi bật khi kêu. Ngón chân mạnh mẽ, màu xám sừng, phủ lông một phần. Móng vuốt màu nâu sẫm, đầu vuốt màu đen. Con non hoàn toàn bao phủ bởi lớp lông màu trắng kem.^[5]

Chiều dài của Cú đại bàng Verreaux trong khoảng 60–66 cm. với sải cánh trung bình dài 140 cm. Trọng lượng cơ thể con trống là 1,600-2,000 g, với trung bình 1.700 g, trong khi trọng lượng cơ thể của con mái là 2,500-3,150 g, trung bình là 2,625 g. Các số đo tiêu chuẩn: cánh, con trống 42–48 cm, con mái 45–49 cm, đuôi con trống 22-27,5 cm, con mái 23–27 cm và xương cổ chân là 8 cm.^[3][6]

Phân bố và môi trường sống

Cú đại bàng Verreaux được tìm thấy trên nhiều vùng hạ Sahara châu Phi, mặc dù nó không có mặt tại sa mạc Namib và hầu hết các khu rừng nhiệt đới ẩm châu Phi. Chúng có mật độ cao nhất ở miền đông và miền nam châu Phi. Chúng sinh sống chủ yếu ở vùng bán sa mạc hoặc xavan khô với cây cối thưa thớt và thảm thực vật gai góc. Chúng cũng tới vùng rừng ven sông tiếp giáp với hoang mạc và các vùng cây cối nhỏ, nửa trống trải được bao quanh bởi vùng đất trống trải, mặc dù chúng không thích môi trường sống có nhiều cây cối. Họ có thể sinh sống ở nhiều độ cao, từ mực nước biển đến 3.000 m.^[3][5]

Lối sống

Cú đại bàng Verreaux là loài chim ăn đêm và ngủ trên cây vào ban ngày trên những cành ngang của cây cổ thụ cao. Cặp chim bố mẹ và con cái của chúng thường xuyên đậu cùng nhau và có thể tham gia vào các giao tiếp lẫn nhau trong thời gian này.^[5]

Cú đại bàng Verreaux được coi là một động vật ăn thịt đỉnh, có nghĩa là nó là nằm ở gần đầu của chuỗi thức ăn và cá thể trưởng thành khỏe mạnh không có kẻ thù tự nhiên. Chúng săn chủ yếu vào buổi tối mặc dù cũng quan sát thấy chúng tấn công con mồi vào ban ngày. Khi đi săn, những con cú này thường bay đến một cành cây khác với cành cây mà chúng ngủ ban ngày. Chúng chủ yếu săn bằng cách lao xuống con mồi từ một cành cây.

Cú hoàn toàn trưởng thành săn một loạt các con mồi, trong đó động vật có vú kích thước trung bình và các loài chim lớn là những con mồi được ưa thích. Con mồi là động vật có vú thông thường bao gồm khỉ nhỏ, chuột thỏ, thỏ rừng, cầy genet, thỏ đá, cầy mangut, sóc đất, dơi ăn quả và các loài chuột khác nhau. Chúng là một trong số rất ít các loài chim xem Nhím gai như con mồi. Khi nhím gai bị bắt, giống như Cú đại bàng Á Âu, lớp da có gai nhọn trên lưng được bóc và bỏ đi.^[7]

Con mồi là các loài chim có thể có kích thước từ chim sâu (chim thợ dệt và chim mỏ sáp) đến diệc lớn và Ô tác, bao gồm cả gà francolins, gà Phi, vịt, và con non của cac loài kền kền, đại bàng, chim mỏ sừng....^[8] Con mồi khác tương đối đa dạng, bao gồm các loài bò sát, ếch, cá và các động vật chân đốt bao gồm cả côn trùng, rết, bọ cạp và nhện. Chúng cũng ăn cả các loài côn trùng bay.

Cú đại bàng Verreaux đã được ghi nhận khi bay mang theo một con cầy mangut nặng hơn 1,8 kg hay thậm chí đã giếp và quắp theo một con khỉ vervet sắp trưởng thành lớn hơn. Nhiều con mồi rất lớn, chẳng hạn như lợn con và Ô tác, có thể là quá nặng đối với các con cú psăn mồi và, trong trường hợp này, sẽ bị bỏ lại tại khu vực bị giết và cả hai con cú trong một cặp sẽ quay trở lại và ăn nhiều lần.^[8]

Thỉnh thoảng, Cú đại bàng Verreaux săn bằng cách bay thấp hơn một bụi cây rồi bất ngờ bắt con mồi trong tán lá rậm rạp như vượn cáo galago hoặc một con mồi sống trên cây khác. Chúng đôi khi cũng chạy sau khi con mồi trên mặt đất hoặc lội vào vùng nước nông để bắt cá. Khi ở gần thành phố, con mồi của chúng có thể bao gồm các sinh vật đô thị phổ biến như chuột và chim bồ câu. Mặc dù chúng sinh sống chồng chéo trong cùng phạm vi với một số loài chim ăn thịt, bao gồm cả các loài đại bàng lớn hơn như Đại bàng vương miện, đại bàng martial và đại bàng Verreaux, chúng hiếm khi tiếp xúc và cạnh tranh với nhau do khác nhau về thời gian hoạt động. Tuy nhiên, các loài cú khác, bao gồm cả loài Dù dì Pel rất lớn, cũng là con mồi tiềm năng của cú đại bàng Verreaux.^[8]

Sinh sản

Mùa sinh sản của cú đại bàng Verreaux diễn ra từ tháng Ba đến tháng Chín.^[9] Mỗi cặp vợ chồng bảo vệ lãnh thổ của mình bằng tiếng kêu của chúng và đôi khi (mặc dù hiếm khi) là song ca. Thường thì việc sinh sản xảy ra hàng năm, nhưng khi mật độ thức ăn giảm, có thể diễn ra mỗi 2 hoặc 3 năm một lần. Chúng sử dụng một loạt các nơi khác nhau để làm tổ, bao gồm tổ của nhiều loài chim khác để lại. Nó thỉnh thoảng cũng làm tổ trên cac hốc cây hoặc trên đám dây leo hoặc phong lan.^[8] Con mái đẻ hai quả trứng màu trắng, kích thước 62,6 mm × 51,4 mm và cân nặng 93-101,6 g, trong khoảng thời gian đến 7 ngày. Thời gian ấp trứng 33-39 ngày. Con mái ở lại trong tổ trong toàn bộ thời gian ấp trứng trong khi con trống đi săn và cung cấp thức ăn cho cả hai.

Sau khi nở, chim non nặng 60-70 g và gần như đã có mí mắt màu hồng rõ ràng. Trứng đầu tiên nở là con đầu tiên được cho ăn, và nếu thực phẩm không đủ, con thứ hai thường bị bỏ đói đến chết. Nếu thức ăn dồi dào, cả hai con cú nhỏ sẽ được cho ăn và có thể tồn tại. Con mái ấp chim non tiếp tục trong 20 ngày. Động vật xâm nhập quá gần với tổ sẽ bị tấn công. Con non sẵn sàng rời khỏi tổ khoảng 63 ngày tuổi nhưng chỉ bay được khoảng 2 tuần sau đó. Các chim non được ẩn nấp và không hoạt động khoảng 3 tháng,và chỉ bắt đầu bắt mồi vào khoảng 5 tháng tuổi. Một số con non có thể ở lại với chim bố mẹ cho đến 2 năm. Tuổi thành thục sinh dục đạt được ở mức 3-4 tuổi. Có rất ít dữ liệu về tuổi thọ ở chim trưởng thành hoang dã, mặc dù những cá thể bị giam cầm đã sống tới 15 năm.^[5]

Tình trạng

Cú đại bàng Verreaux là một loài hiếm gặp, do mật độ thấp và nhu cầu lãnh thổ lớn cho mục đích săn mồi và sinh sản. Đôi khi chúng trở nên hiếm tại một số nơi do bị xua đuổi, bức hại (do là chúng có thể ăn thịt các thú nuôi nhỏ, mặc dù điều này là hiếm) và những ảnh hưởng của thuốc trừ sâu (chất độc tiêu thụ thông qua con mồi có thể bị ảnh hưởng chúng). Tuy nhiên, chúng là phổ biến rộng rãi và hiện không được coi là bị đe dọa ở mức độ loài.^[5]

Hình ảnh

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Chú thích

Tham khảo

• Dữ liệu liên quan tới Bubo lacteus tại Wikispecies

Царство: Животные

Подцарство: Эуметазои

Без ранга: Двусторонне-симметричные

Без ранга: Вторичноротые

Тип: Хордовые

Подтип: Позвоночные

Инфратип: Челюстноротые

Надкласс: Четвероногие

Класс: Птицы

Подкласс: Настоящие птицы

Инфракласс: Новонёбные

Отряд: Совообразные

Семейство: Совиные

Подсемейство: Настоящие совы

Род: Филины

Вид: Бледный филин

Вызывающие наименьшие опасения
IUCN 3.1 Least Concern: 22688986

• 1 Описание
• 2 Распространение
• 3 Питание
• 4 Размножение
• 5 Примечания
• 6 Литература

クロワシミミズク 分類 界 : 動物界 Animalia 門 : 脊索動物門 Chordata 亜門 : 脊椎動物亜門 Vertebrata 綱 : 鳥綱 Aves 目 : フクロウ目 Strigiformes 科 : フクロウ科 Strigidae 属 : ワシミミズク属 Bubo 種 : クロワシミミズク B. lacteus 学名 Bubo lacteus Temminck, 1820 和名 クロワシミミズク 英名 Verreaux's Eagle-owl ウィキメディア・コモンズには、クロワシミミズクに関連するメディアがあります。

クロワシミミズク（黒鷲木菟、学名：Bubo lacteus）は、フクロウ目フクロウ科に分類される鳥類の一種。

形態[編集]

羽毛は黒に近い灰色。目の虹彩は黒く、頭部に耳のような形の羽毛が生えている。上まぶたがピンク色で足の指に短い羽毛があるのが特徴。

Sibley分類体系上の位置[編集]

シブリー・アールキスト鳥類分類

この項目は、鳥類に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（ポータル鳥類 - PJ鳥類）。