Through their predation on flying insects, bank swallows can help to control populations of pest insects, such as mosquitoes and agricultural pests.
Positive Impacts: controls pest population
Bank swallows that live in larger colonies are better able to detect and defend against avian predators. They cooperate to mob predators that threaten their colony. Most predation is on nestlings and eggs in burrows. Eurasian badgers (Meles meles) have been observed excavating burrows and it is likely that other terrestrial mammals attempt to take advantage of bank swallow colonies. Snakes are important predators of nestlings, including gopher snakes (Pituophis catenifer sayi) and black rat snakes (Pantherophis obsoletus) in North America. American kestrels (Falco sparverius), hobbies (Falco subbuteo), and other bird-specialist raptors will attempt to take flying adults and inexperienced fledglings. Bank swallows are often unsuccessful in deterring predators via mobbing. They have been observed deterring predation by blue jays (Cyanocitta cristata), however.
Known Predators:
Bank swallow populations worldwide vary slightly in plumage color and size, but variation seems to be clinal. Their ability to disperse over very large distances suggests that gene flow can occur at continental levels at least. At one point 8 subspecies were recognized, but currently only 3 subspecies worldwide are recognized: R. r. riparia, a cosmopolitan subspecies, R. r. diluta a subspecies found throughout northern and central Asia, and R. r. shelleyi, found from Egypt to northeastern Africa.
Bank swallows are smallish swallows with grayish-brown plumage on the head, back, wings, and tail. The flight feathers of the wings and tail have a slightly darker plumage color and there is a brown band that stretches across the breast. The chin, throat, belly, and undertail coverts are white. Juveniles may have buffy or whitish upperparts and a pink wash to the throat. Their tails are slightly notched.
Bank swallows can be confused with other, small brownish swallows. In North America this includes northern rough-winged swallows (Stelgidopteryx serripennis), which lacks the breast band, and juvenile tree swallows (Tachycineta bicolor), which are larger and differ in some plumage characteristics. In South America they may be confused with brown-chested martins (Progne tapera), which are much larger (30-40 g). Bank swallows may also be distinguished by their voice and their flight pattern: they hold their wings at a sharp angle in flight and use quick, flicking wing beats.
Average daily metabolic rates for bank swallows have been measured at 8.99 to 11.55 cm3 CO2/g/hr.
Range mass: 10.2 to 18.8 g.
Average length: 12 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
The yearly recruitment of bank swallows may be strongly influenced by conditions in the wintering habitat, which influence survival of juveniles. A study of a Hungarian population that winters in the Sahel region of Africa, suggested that winter, Sahelian rainfall was related to adult population size in the following year on the breeding range. Average annual mortality estimates for adults are approximately 60%, mortality in juveniles is higher. Two bank swallows lived to 9 years old in the wild.
Bank swallows are susceptible to the effects of unseasonably cold weather, which makes it difficult for them to find insect prey and meet their energy demands. Nestlings also die when burrows collapse.
Range lifespan
Status: wild: 9 (high) years.
Their scientific name (Riparia riparia) refers to the preferred breeding habitat of bank swallows. They nest in small to large colonies in soft banks or bluffs along rivers, streams, and coastal areas. They prefer the eroding banks of low-gradient, meandering rivers and streams. They also use sandy coastal bluffs or cliffs. Man-made habitats are now also used, including gravel pits, quarries, and road cuts. They are found from sea level to 2100 meters elevation, but most populations occur in lowland river valleys and coastal areas. Important foraging habitats include wetlands, large bodies of water, grasslands, agricultural areas, and open woodlands. Bank swallows mainly migrate along large bodies of open water, such as marshes, coastal areas, estuaries, and large rivers. In winter they are seen mainly in open habitats with large bodies of water and grasslands, savannas, or agricultural areas.
Range elevation: 0 to 2100 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: savanna or grassland ; scrub forest
Aquatic Biomes: lakes and ponds; rivers and streams; coastal
Wetlands: marsh
Other Habitat Features: agricultural ; riparian ; estuarine
Bank swallows, or sand martins as they are known in Europe and Asia, are one of the few small passerine birds that have an almost cosmopolitan distribution. They migrate between discrete breeding and wintering ranges. Bank swallow distribution in the breeding range is most limited by suitable nesting habitat. Winter distribution is influenced by appropriate foraging areas.
In the Americas, bank swallows breed throughout much of Alaska and Canada to the maritime provinces and south to the mid-Atlantic United States, throughout much of the Appalachian chain, along the Ohio River Valley to Missouri, west throughout much of Kansas, along the Rocky Mountain Chain into New Mexico, and in the mountainous regions of Utah, Nevada, and northeastern California. They also breed along the Rio Grande river in Texas and northern Mexico. In winter, American populations migrate to throughout South America and along the western coastal slopes of Mexico. They are rare visitors to some Antillean islands in winter.
In the Old World, bank swallows (or sand martins) breed throughout northern Eurasia, from the British Isles, across Scandinavia, northern Russia, and Siberia, and as far south as the Mediterranean, Middle East, the Nile River valley, northern, coastal Africa, northwestern Africa, Iran, Afghanistan, India, and Pakistan to as far east as southeastern China and Japan. They winter throughout the Arab Peninsula and Africa, including Madagascar. They can also be found throughout much of southern and southeastern Asia in winter, including the Philippine Islands.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); oriental (Native ); ethiopian (Native ); neotropical (Native ); oceanic islands (Native )
Other Geographic Terms: holarctic ; cosmopolitan
Bank swallows eat almost exclusively insects that they catch in flight. Insect prey are generally flying insects, although occasionally they take terrestrial or aquatic insects or insect larvae. Most foraging occurs over bodies of water or large areas of short-growing vegetation, such as meadows, agricultural fields, or wetlands. They sometimes forage over forest canopies. Bank swallows drink in flight as well, by skimming the water surface with their lower mandible. The size of colonies may impact whether individuals can get information on the location of prey from other individuals. In North America, swallows in relatively small colonies (5-55 pairs) did not transmit information on foraging to others. In Hungary, however, swallows in a large colony (2100 pairs) foraged synchronously and seemed to transmit information on foraging to other colony members. Breeding adults generally forage within 200 m of their nest, although they may have to forage farther away. If foraging distances are higher, parents return to nests with larger food boluses.
Bank swallows forage from dawn to dusk. One study of stomach contents suggested 99.8% of bank swallow diet is insects, with approximately 33.5% ants, bees, and wasps (Hymenoptera), 26.6% flies (Diptera), 17.9% beetles (Coleoptera), 10.5% mayflies (Ephemeroptera), 8% bugs (Hemiptera), 2.1% dragonflies (Odonata), and 1.2% moths and butterflies (Lepidoptera). Other studies yielded similar results, although proportions of prey varied by region and season.
Animal Foods: insects
Primary Diet: carnivore (Insectivore )
Bank swallows that live in larger colonies suffer higher rates of flea infestation and nestlings with fleas had lower body masses than nestlings without fleas. Flea species include Ceratophyllus styx, Celsus celsus, and Ceratophyllus riparius. Larval blowflies parasitize bank swallows as well, including Protocalliphora splendida, Protocalliphora braueri, Protocalliphora hirundo, Protocalliphora metallica, Protocalliphora sialia, and Protocalliphora chrysorrhoea. This last species seems to be restricted to the nests of bank swallows throughout the Holarctic. Mites (Liponyssus sylviarum, Atricholaelaps glasgowi), lice (Myrsidea dissimilis), feather lice (Mallophaga), and nematodes (Acuaria attenuata) are also found in bank swallows.
Bank swallows are important predators of flying insects, especially where they concentrate around breeding colonies. European starlings and house sparrows may take over their burrows. Other sand and bank burrowing birds, such as kingfishers, barn owls, northern rough-winged swallows, and cliff swallows are tolerated by bank swallows.
Mutualist Species:
Commensal/Parasitic Species:
There are no known adverse effects of bank swallows on humans.
Bank swallows are widespread and population sizes are large. The IUCN considers them "least concern." However, local populations are impacted by loss of nesting habitat. In California they are listed as threatened, they are considered sensitive in Oregon, and a species of special concern in Kentucky. Bank swallows are fairly tolerant of human activities and will even nest in active quarries.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Young bank swallows use a food-begging call and a signature call to their parents at the nest. Parents recognize the calls of their own offspring. Parents respond with a feeding call when they return to the nest to feed their young, the feeding call is described as a set of sweet notes. Contact calls are the most commonly used call and are described as a raspy or strident "tschr." Males also sing to advertise territories and attract females for mating. Males can sing at the nest and in flight. The song sounds like a rapid repetition of the contact call, giving it a chattering quality. Bank swallows also use warning and alarm calls when they observe predators. Warning calls are given to colony-mates while alarm calls are directed at predators when they are being mobbed.
Males also perform display flights to attract females.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Bank swallows are monogamous and defend their nesting site together. Males begin to excavate burrows when they arrive on their breeding grounds. Preferred burrow sites are in soft, but stable soils, most often higher on banks or slopes. Burrows are dug perpendicular to the bank face and average 58.8 cm in length when complete. Once the nest burrow is about 30 cm long, they will begin to sit in the entrance and sing to attract females. They will also perform flight displays outside of the burrow entrance to attract females. The pair bond is formed as a female begins to sing in response to the male and perch near the burrow. Males and females will sleep together in the nest burrow and most copulations occur there.
Both sexes, however, will attempt extra-pair copulations. Male bank swallows assess female mass via flight characteristics, such as speed of ascent, in order to determine which females are most likely to be in a pre-laying or laying condition. Females that are heaviest are also at their most fertile condition, making them the best targets for attempts at extra-pair copulations. However, both sexes also guard their mates so extra-pair copulations may not be terribly common.
Mating System: monogamous
Once a mated pair is formed at an excavated burrow, females will begin building a nest in the burrow, along with helping with any additional excavation. Nests are lined with grass, feathers, and other fine materials in the area. Females begin to lay eggs as early as April and into July in some areas. Most pairs attempt only 1 clutch per year, unless their first clutch is destroyed early in the nesting season. Females lay from 1 to 9, but usually 4 to 5, white eggs every day until the full clutch size is reached. Females begin incubating the clutch 1 to 2 days before all eggs are laid. Incubation takes 13 to 16 days and eggs hatch over the course of several days. Hatching in colonies is generally synchronous. Fledging occurs at around 20 days after hatching and parents continue to feed their young for 3 to 5 days after fledging. Once they become independent, young bank swallows gather in flocks of juveniles and adults. They are forced away from their natal burrow by their parents, but often gather in small groups at other burrows to rest. Males and females can breed in their first year after hatching.
Breeding interval: Bank swallows generally have 1 clutch yearly.
Breeding season: Bank swallows breed during spring and summer in the Northern Hemisphere.
Range eggs per season: 1 to 9.
Average eggs per season: 4-5.
Range time to hatching: 13 to 16 days.
Average fledging age: 20 days.
Range time to independence: 23 to 25 days.
Average age at sexual or reproductive maturity (female): 1 years.
Average age at sexual or reproductive maturity (male): 1 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Male and female bank swallows share in incubating young, which allows them to lay eggs earlier in the season, when the weather is colder, than other swallow species (Hirundinidae) in which females only incubate eggs (such as Hirundo rustica). However, females do most incubation. Both parents sleep in the nest burrow at night. Young are altricial at hatching and parents brood them for 7 to 10 days. Both parents feed the young and help to protect them from predators until they are 23 to 25 days old, a few days after they have left the nest burrow.
Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female)
Migrant breeder, regular passage visitor and winter visitor?
A small (4 ½ to 5 ½ inches) swallow, the Bank Swallow is most easily identified by its brown upperparts, white belly white throat, and dusty brown chest stripe separating the throat from the belly. This species may be separated from the similarly-patterned Northern Rough-winged Swallow (Stelgidopteryx serripennis) by that species’ larger size and brown chin. The Bank Swallow occurs across much of the world. In the Americas, this species breeds from Alaska and central Canada south locally to the Mid-Atlantic region in the east and northern Mexico in the West, wintering on the Pacific coast of Mexico and further south to central South America. In the Old World (where it is known as the Sand Martin), this species breeds across Eurasia from Siberia south to North Africa and the Indian subcontinent, wintering across tropical Africa and South Asia. Historically, Bank Swallows bred in a variety of habitats near water, frequently building their nests on cliffs along the banks of rivers. Today, this species often nests on man-made structures such as buildings and bridges. In winter, this species is likewise found in habitats near water, including lakes, rivers, marshes, and reservoirs. Bank Swallows exclusively eat flying insects. As is the case with most swallow species, it is possible to observe Bank Swallows feeding on insects while in flight. Birdwatchers in this species’ breeding range may want to pay special attention to bridges or the eaves of buildings, as a careful search of these structures may reveal a nesting colony. Bank Swallows are primarily active during the day.
The Sand Martin is interesting in that it is capable of sustained flight from the first time that it launches itself from its nest hole. This is necessary for a Sand Martin to survive as, traditionally, the nest hole was, and often still is, in a sheer cliff face, often above water. It gains this ability over a number of days by flapping its wings vigorously in the nest/hole to strengthen them, then pressing its primary wing feathers and tail hard down onto the nest/hole at an angle of 45 until it is able to support its body by these alone. When it is able to support its body by its wings and tail alone for more than a few seconds, then, instinctively, it will launch itself from the nest hole.
A small (4 ½ to 5 ½ inches) swallow, the Bank Swallow is most easily identified by its brown upperparts, white belly white throat, and dusty brown chest stripe separating the throat from the belly. This species may be separated from the similarly-patterned Northern Rough-winged Swallow (Stelgidopteryx serripennis) by that species’ larger size and brown chin. The Bank Swallow occurs across much of the world. In the Americas, this species breeds from Alaska and central Canada south locally to the Mid-Atlantic region in the east and northern Mexico in the West, wintering on the Pacific coast of Mexico and further south to central South America. In the Old World (where it is known as the Sand Martin), this species breeds across Eurasia from Siberia south to North Africa and the Indian subcontinent, wintering across tropical Africa and South Asia. Historically, Bank Swallows bred in a variety of habitats near water, frequently building their nests on cliffs along the banks of rivers. Today, this species often nests on man-made structures such as buildings and bridges. In winter, this species is likewise found in habitats near water, including lakes, rivers, marshes, and reservoirs. Bank Swallows exclusively eat flying insects. As is the case with most swallow species, it is possible to observe Bank Swallows feeding on insects while in flight. Birdwatchers in this species’ breeding range may want to pay special attention to bridges or the eaves of buildings, as a careful search of these structures may reveal a nesting colony. Bank Swallows are primarily active during the day.
The Sand Martins breeding in the Western Palearctic and wintering in the Western Sahel region of Africa are double-brooded, (1) or more definitively, multi-brooded (2,3). In one Study over an 18 year period at one site in Scotland at longitude 1W, the degree of multi-brooding was assessed.(4) The percentage of 1349 successful broods appearing in nest holes holding one brood during a season was 37%, nest holes holding two broods 62%, and nest holes holding three broods 1%. During the same study, male Sand Martins occupied a nest hole through the whole of the breeding season unless they died through predation or from other causes. The multi-brooding occurs when females whose mates are capable of provisioning a brood alone, are left to do so when the females start a new clutch with a new mate, thus improving their own productivity. (3,5.)
In a study in central Europe at longitude 21E (6) it was found that seasons when there were no second broods did not affect the population size in the following breeding season. However, in Britain (7) surviving juveniles from those fledging during June, July and August, covering the first and second brood periods, were found to contribute to the following years breeding population.
This multi-brooding behaviour is quite distinct from those Sand Martins breeding throughout most of the Holarctic region which are decidedly single brooded (8,9). It was found (10) that the breeding population in Britain fell by over 90% between 1968 and the mid 1980's when there were particularly severe droughts in the Western Sahel region. Such losses of population are caused by these Sahelian droughts (6,11,12,13,), and also by adverse weather, mainly torrential or prolonged precipitation during periods when the Sand Martins are provisioning young (Cowley14.). This precipitation results from the temperate maritime climate of Britain.
The breeding biology; clutch size and development of eggs and young, is similar throughout its Holarctic range, (8,9,15). However, there is a difference in the survival rate, it normally being lower amongst the Sand Martins breeding in the Western Palearctic.(8,15).
The sand martin (Riparia riparia), also known as the bank swallow (in the Americas), collared sand martin, or common sand martin, is a migratory passerine bird in the swallow family. It has a wide range in summer, embracing practically the whole of Europe and the Mediterranean countries and across the Palearctic to the Pacific Ocean. It is a Holarctic species also found in North America. It winters in eastern and southern Africa, South America, and the Indian Subcontinent.
This species was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae, and originally named Hirundo riparia; the description consisted of the simple "H[irundo] cinerea, gula abdomineque albis" – "an ash-grey swallow, with white throat and belly" – and the type locality was simply given as "Europa".[3] The specific name means "of the riverbank"; it is derived from the Latin ripa "riverbank".[4]
The pale martin of northern India and southeastern China is now usually split as a separate species Riparia diluta. It has paler grey-brown upperparts and a less distinct breast band. It winters in Pakistan southern India and Sri Lanka.[5]
The sand martin is brown above, white below with a narrow brown band on the breast; the bill is black, the legs brown. The young have rufous tips to the coverts and margins to the secondaries.
Its brown back, white throat, small size and quick jerky flight separate it at once from similar swallows, such as the common house martin (Delichon urbicum), the American cliff swallow (Petrochelidon pyrrhonota) or other species of Riparia. Only the banded martin (Neophedina cincta) of sub-Saharan Africa is similar, but the sand martin only occurs there in (the northern) winter.
Measurements:[6]
The sand martin's twittering song is continuous when the birds are on the wing and becomes a conversational undertone after they have settled in the roost. The harsh alarm is heard when a passing falcon, crow or other suspected predator requires combined action to drive it away.
Linnaeus already remarked on this species' breeding habits: Habitat in Europae collibus arenosis abruptis, foramine serpentino—"it lives in Europe, in winding holes in sheer sandy hills". It has been observed that sand martins favour loess as a particular type of ground to nest in.[7] Sand martins are generally found near larger bodies of water, such as rivers, lakes or even the ocean, throughout the year.[3][8]
In Britain, the sand martin appears on its breeding grounds as the first of its family, starting towards the end of March, just in advance of the barn swallow. In northern Ohio, they arrive in numbers by mid-April, about 10 days earlier than they did 100 years ago.[9][10] At first, they flit over the larger bodies of water alone, in search of early flies. Later parties accompany other swallow species, but for a time, varying according to weather, the birds remain at these large waters and do not visit their nesting haunts. The sand martin departs early, at any rate from its more northerly haunts. In August, the gatherings at the nightly roost increase enormously, though the advent and departure of passage birds causes great irregularity in numbers. They are essentially gone from their breeding range by the end of September.
Their food consists of small insects, mostly gnats and other flies whose early stages are aquatic.
The sand martin is sociable in its nesting habits; from a dozen to many hundred pairs will nest close together, according to available space. The nests are at the end of tunnels ranging from a few inches to three or four feet in length, bored in sand or gravel. The actual nest is a litter of straw and feathers in a chamber at the end of the burrow; it soon becomes a hotbed of parasites. Four or five white eggs are laid about mid-late May, and a second brood is usual in all but the most northernly breeding sites.
Globally, it is not rare and classified as a species of least concern (but noted to be decreasing)[11] by the IUCN.[1] It does have some national and local protections, as certain populations have declined or face threats from habitat loss and fragmentation. In Canada, it is listed as Threatened under Schedule 1 of the federal Species at Risk Act (SARA) due to the loss of 98% of its Canadian population over the past 40 years.[12] They are considered threatened in California, where populations exist in the Sacramento Valley[13] and at two coastal sites, Año Nuevo State Park and Fort Funston.[14]
Showing dark breast band
Active breeding colony
_-_Nest_-_Ystad-2021.jpg){kind=small}
Abandoned breeding colony
Nest with egg
Eggs, Collection Museum Wiesbaden, Germany
The sand martin (Riparia riparia), also known as the bank swallow (in the Americas), collared sand martin, or common sand martin, is a migratory passerine bird in the swallow family. It has a wide range in summer, embracing practically the whole of Europe and the Mediterranean countries and across the Palearctic to the Pacific Ocean. It is a Holarctic species also found in North America. It winters in eastern and southern Africa, South America, and the Indian Subcontinent.
