Common waxbills use both song and body language to communicate. The song of Estrilda astrild is a soft, simple call with notes varying only slightly in pitch and length from the contact note. A common body movement for this species is a “curtsy”, where the body is crouched with the head slightly turned, accompanied by soft singing. Females will sing more smoothly during this display, while males sing in a shorter series of notes. To impress a female, males fluff their feathers, point their bills upwards, and position their bodies so that their red underbellies are displayed clearly. Strong lateral movements with the tail are also used by both sexes during a number of different social encounters. Mates will perform mutual preening to establish or strengthen their pair-bond. Like all birds, common waxbills perceive their environment through visual, tactile, auditory and chemical stimuli.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Common waxbills are not a threatened species. They are, instead, presently expanding their range and populations into new regions.
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Common waxbills can be detrimental to crops in some areas. This seems to be most often reported in regions where waxbills are non-native. Tomato crops in Cape Verde are one documented case which Estrilda astrild populations had a directly negative impact.
Negative Impacts: crop pest
Estrilda astrild finches are frequently kept caged as songbirds for human enjoyment.
Positive Impacts: pet trade
Common waxbills have different ecological roles depending on their location. In their native African landscape they have a minimal impact on the plant species they eat. However, this is not the case in some of the regions where they have been introduced. In Cape Verde and Seychelles, for example, invasive common waxbill populations have been shown to have a destructive impact on the crops they consume. As granivores, common waxbills likely play a significant role in seed dispersal for plants they consume.
Despite its role as an invasive species, there are no reports showing that common waxbills will serve to displace native species. In Brazil, a relatively new range for Estrilda astrild, they are reported to feed mostly on introduced grass species which are eaten only sparingly by native Brazilian bird species. Therefore it is seen as unlikely that common waxbills will displace any native bird species in that region.
The nests of common waxbills are known host sites for pin-tailed whydahs (Vidua macroura), a well known brood parasite. Pin-tailed whydah chicks have evolved gape patterns that exactly match the gape patterns of common waxbill young, so that they are more likely to be accepted by waxbill parents. This relationship is harmful to the breeding success rate of common waxbills, but essential to the survival of pin-tailed whydahs.
Ecosystem Impact: disperses seeds
Commensal/Parasitic Species:
Common waxbills are granivores, living on a diet mainly of seeds from pasture grasses and millets. Of these, guinea grasses (Panicum maximum) are perhaps the most important dietary components for waxbills as they have seed heads available year-round. Other important seed prodeucers include crabgrass (Digitaria horizontalis) and Echinochloa species. Depending on a plant’s structure, common waxbills may either perch on the panicle while plucking seeds, or will pull the panicle to the ground, holding the plant with one foot and steadying itself on the ground with the other. Seed removal is done with the bill in both cases. They forage in flocks of 2 to 20 during the day, feeding mostly in early morning and late afternoon.
Plant Foods: seeds, grains, and nuts
Primary Diet: herbivore (Granivore )
Common waxbills (Estrilda astrild) are native across much of sub-Saharan Africa. The species has been introduced to the Americas, the Mediterranean Basin, and Oceania. A high reproductive rate and ability to adapt to new food sources have allowed common waxbills to successfully naturalize in many of the areas to which it has been introduced. While most of these introductions are thought to result from the escape of caged individuals, some regions have introduced flocks deliberately.
Biogeographic Regions: nearctic (Introduced ); palearctic (Introduced ); ethiopian (Native ); neotropical (Introduced ); australian (Introduced ); oceanic islands (Introduced )
Common waxbills inhabit damp grassy areas, preferring those near wetlands. They breed and nest among reed beds, tall grasses, riverside vegetation, and dense bushy cover. They may also be found in a number of open mesic habitats such as farmlands and parks.
Habitat Regions: temperate ; tropical ; terrestrial
Terrestrial Biomes: savanna or grassland
Wetlands: marsh
Other Habitat Features: urban ; suburban ; agricultural ; riparian
Common waxbills live an average of 4 years in the wild.
Average lifespan
Status: wild: 4 years.
Estrilda astrild is a small grey-brown colored finch, distinguished by its red conical bill and face patch. The bill looks as if it has been dipped in red wax, providing explanation to the origin of their common name, common waxbills. The cheeks, throat, and belly are a whitish-grey color, while the rest of the plumage is finely barred and the underside has a dusting of red. Adult common waxbills have a wingspan between 12 and 14 cm, and length of about 11.5 cm. They weigh approximately 8.9 g. The species has a fairly long, slender tail and rounded wings. Females are paler overall with less red along the belly. The plumage of juveniles is duller than the adults, having little red on the underbelly, and no red on the bill. Nestlings have obvious white gape flanges along the edges of their mouths.
According to Traylor et al., there have been 16 recognized subspecies of Estrilda astrild. However, there is very little information available on these subspecies. Black-lored waxbills (Estrilda nigriloris), was once considered a subspecies of common waxbills, but is now recognized as its own species.
Average mass: 8.9 g.
Average length: 11.5 cm.
Range wingspan: 12 to 14 cm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes colored or patterned differently; male more colorful
Common waxbill young have an increased risk of predation as a result of their nests being placed so close to the ground. Mice and snakes are examples of the types of predators that will target common waxbill eggs and young. In a defensive response to this, the parents spread carnivore scat in and around the nest site to deter predators. The most commonly used scat comes from servals (Leptailurus serval), a type of large, African cat. The odor of the scat may be working to both deter predators from approaching the area, and also to mask the smell of the eggs and young themselves.
Known Predators:
Finches of the genus Estrida are monogamous, mating with only one partner. Song and display are both important aspects of courtship, and pair formation usually begins with a "curtsy" and song exchange between the two prospective mates. Allopreening occurs frequently between the mates. During the nest building and solicitation period, both males and females may participate in stem displays to their mates – a form of display during which a stem is held in the beak. The male sings an irregular pattern during this a display, while the female remains silent. After pairing off, they separate from the larger flock and breed singly. They may, however, be found in small territories adjacent to other pairs.
Males will also display to other females in the flock (those which are not his mate), but this display does not begin with a curtsy and is a type of “fluffed singing”. During this display the male positions his body to present the female with his red belly patch. He does this by placing one flank toward the female and outstretching his neck, holding his head high. He fluffs up his ventral and flank feathers, twists his tail toward the female, and the sings loudly. Females almost always flee when they receive these displays, being that they are advances from males with whom they are not mated. Males will attempt to mate with females which do not flee from his advances.
Mating System: monogamous
The breeding season for Estrilda astrild takes place in midsummer, except in winter-rainfall areas (such as Southern Africa) where the breeding season is between September and January. The nest is a weaved, spherical mass of grasses with a narrow entrance. Nests are generally on or near the ground, hidden in similar, grassy vegetation. They have a clutch size between 4 and 6 eggs, and may raise several broods a year. The incubation period lasts 11 to 12 days with both sexes working to incubate the eggs. Fledging takes 17 to 21 days and during this time both parents feed and care for the chicks. Common waxbill juveniles reach reproductive maturity between 6 months and 1 year of age.
Breeding interval: Common waxbills may raise several broods a year.
Breeding season: Common waxbills mate in midsummer in most locations, and between January and September for winter-rainfall areas.
Average eggs per season: 4 to 6.
Average time to hatching: 11 to 12 days.
Average fledging age: 17 to 21 days.
Range age at sexual or reproductive maturity (male): 6 to 12 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Common waxbills build spherical nests out of dry grasses and keep them hidden in reeds close to the ground. The female does most of the nest-building, but the male assists in decorating it and lining the inside with feathers. Both parents spread animal scat in the nest throughout the nesting period as a way to divert predators. A unique feature to common waxbill nests is the formation of a separate “cock’s nest” located atop the main nest. No one is certain what the purpose of this secondary nest is, but it appears to be a resting place for the parent who is not incubating the nest.
Both male and female common waxbills incubate and feed the helpless, altricial young. The nests of common waxbills are often utilized by brood parasites such as pin-tailed whydahs (Vidua macroura), and the waxbill parents dotingly care for these parasitic young alongside their own.
Parental Investment: altricial ; male parental care ; female parental care ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female)
