WAXBILLS AND GRASSFINCHES: Estrildidae

PHYSICAL CHARACTERISTICS

Waxbills and grassfinches, commonly called weaverfinches, are relatively small, often brightly colored birds with large, cone-shaped bills. Projections (or swellings) of thick connective tissue, which are located at the edges of the bill and at the gape (width of the open mouth), are one of the weaverfinches most interesting features. The projections are colored a bright white, blue, or yellow, and often edged with black. Their plumage (feathers) often blends in with their environment, but can still be quite colorful. Adults are 3.5 to 6.7 inches (9 to 17 centimeters) long, with a wingspan of about 6 inches (15 centimeters).

GEOGRAPHIC RANGE

They are found in sub-Saharan Africa, southeastern Asia, Australia, and South Pacific islands. Various small populations have been introduced throughout other parts of the world.

HABITAT

Weaverfinches are found in savannas (flat grasslands), forests, and semi-deserts, preferring forest edges.

DIET

Their diet consists of small half-ripe and fully ripe grass seeds, and during the breeding season they also eat arthropods (invertebrate animals with jointed limbs). Ants and termites are eaten at the beginning of the rainy season. They often dash out from a perch to grab an insect and then return to the same perch.

BEHAVIOR AND REPRODUCTION

Weaverfinches are highly social birds that maintain strong bonds between the mating pair and among members of small flocks. They often perch in close contact with each other, often preening each other (grooming feathers with the bill). Males do a dance for females where they sing and either hop toward the female, or perform bows or stretching movements while hopping about in front of the female. If interested, females will cower on a branch and tremble her tail (that is, shake it slightly while keeping the wings still).

The song of weaverfinches is usually soft. Weaverfinches do not use songs to defend their territory or show aggression. The short song often sounds unpleasant, and is usually heard only by a nearby female as part of the courtship ritual. Songs are learned while in the fledgling period (time necessary for young bird to grow feathers necessary to fly).

Nests of weaverfinches are often roofed over, and shaped like a sphere (ball) with a diameter of 4 to 8 inches (10 to 20 centimeters). Many species attach a long tube to the nest that is used as an entrance. Males gather the nesting materials that consist of fresh or dry grass stalks, coconut fibers, animal hair, and feathers (for the nest itself) and feathers and other soft materials (for the lining). Females weave very complex nests, which is often also used for roosting during the nonbreeding season. Nests are usually placed in bushes or low trees, but can be found on the ground, hanging between reeds or grass stalks, or in tree holes.

Females lay four to six eggs, but once in awhile can lay up to nine eggs. Both sexes incubate (sit on and warm) eggs and brood (raise) young. During the day they switch sitting on the eggs around every one and one half hours, but at night both parents sit on the eggs together. Males often give brooding females a bit of grass or feather. The incubation period (time that it takes to sit on and warm the eggs before they hatch) is twelve to sixteen days. The young eat half-ripe seeds that are regurgitated (food brought up from the stomach) by the parents into their open mouth. The nestling period (time necessary to take care of young birds unable to leave nest) lasts about twenty-one days. Even after the young leave the nest, parents will direct the young birds back into the nest for sleeping and eating. They still take food from the parents from one to two weeks after fledging (first time that young are able to fly away from the nest). Many weaverfinches reach breeding age before their first birthday, sometimes even before they molt from their juvenal (present while a juvenile, young) plumage.

WEAVERFINCHES AND PEOPLE

Weaverfinches are often kept in aviaries (large cages) where a mixed group of different species and colored birds are kept in the same environment. Many species such as the Java sparrow, the zebra finch, and the gouldian finch are domesticated species.

CONSERVATION STATUS

Two species of weaverfinches are listed as Endangered, facing a veryhigh risk of extinction; eight species as Vulnerable, facing a high risk of extinction; and six species as Near Threatened, in danger of becoming threatened with extinction.

COMMON WAXBILL (Estrilda astrild): SPECIES ACCOUNTS

Physical characteristics: Common waxbills are mostly fawn in color, with upperparts that are darker than lower parts, a striped body, red bill, and a red stripe from the bill across the eye to the ear. Males and females look alike, having the same colors. Juveniles look paler than adults and with fainter barring. Adults are 4.3 to 5.1 inches (11 to 13 centimeters) long.

Geographic range: They are found generally in southern Africa, specifically in southern Senegal, east to Ethiopia, south to South Africa, and generally throughout most of sub-Saharan Africa. They have been introduced in Portugal, Brazil, and many islands throughout the world, including Hawaii, Amirantes, Tahiti, Rodriques, Reunion, Mauritius, St. Helena, the Seychelles, Puerto Rico, and Bermuda.

Habitat: Common waxbills live in areas with tall grasses such as marshes, reed beds, abandoned cultivated areas, gardens, grassy paths and clearings, and farms and plantations.

Diet: They eat small seeds (such as grass seeds) taken from plants and off the ground. Termites and other insects are also sometimes eaten.

Behavior and reproduction: Common waxbills are very social birds, often found in small flocks during the breeding season and larger flocks (sometimes numbering in the thousands) at other times. Their calls include such sounds as "chip," "tchic," and "pit" while their song is often described as a "tcher-tcher-preee," although other varieties are often heard. They build a pear-shaped nest of grass stems that is located at or near the ground. Females lay four to six white eggs. The incubation period is eleven to thirteen days, and the fledgling period is about twenty days.

Common waxbills and people: People often keep common waxbills in cages, and have been bred in aviaries.

Conservation status: These birds are not threatened, but their trade (importing and exporting them) is regulated. ∎

ZEBRA FINCH (Taeniopygia guttata): SPECIES ACCOUNTS

Physical characteristics: Adult males have an orange cheek patch, chestnut ear patches, black barring at the throat, red eyes, white-spotted chestnut flanks, black and white bars on the tail, a gray head and back, orange legs, and a red bill. Adult females lack most of the colors of the males, but do have an orange bill. Juveniles look similar to females but have a dark bill. Adults are 3.9 to 4.3 inches (10 to 11 centimeters) long and weigh about 0.4 ounces (12 grams).

Geographic range: They are found throughout most of the interior of Australia (being absent from the north, east, and south coasts) and in Timor (an island in Southeast Asia) and the surrounding Indonesian islands.

Habitat: Zebra finches inhabit a wide variety of habitats but prefer open areas such as plains, woodlands, savannas (flat grasslands), mulga scrubs (acacia [uh-KAY-shuh] trees that grow in arid regions of Australia), grasslands, salt marshes, orchards, cultivated areas and farmlands, and inhabited areas and gardens.

Diet: These birds feed on a variety of grass seeds and shoots, mostly from the ground, but also eat insects. They are able to live up to about 500 days without drinking water.

Behavior and reproduction: Zebra finches are very social birds that are found in pairs but more often found in large flocks. Their call is a "tya" or "tchee." Males courting females give out a mixture of trills and nasal notes. They build flask-shaped nests of many types of materials but mostly of grasses that is lined with feathers and wool. An entrance tunnel is built on the side. Sometimes other bird nests or roosts are used, often redone to suit their own needs. Females lay three to eight white eggs. The incubation period is eleven to sixteen days, and the fledgling period is fifteen to twenty-two days.

Zebra finches and people: People often keep zebra finches as pets. They are often bred, studied, and sometimes domesticated.

Conservation status: Zebra finches are not threatened. ∎

SPOTTED MUNIA (Lonchura punctulata): SPECIES ACCOUNTS

Physical characteristics: Spotted munias look alike with respect to males and females. They have big heads and large, conical bills, brown, scale-patterned feathers on a white breast and flanks, and a dusky brown face and throat. They also have plain brown upperparts and small grayish traces on rump. Juveniles have brown upperparts and buffy under parts, but do not have the scaled pattern on their under parts. Adults are 3.9 to 4.7 inches (10 to 12 centimeters) long.

Geographic range: They range from India, southern China, and Southeast Asia including parts of Malaysia and Indonesia. They have been introduced in Australia, Puerto Rico, Hawaii, Japan, and the Seychelles.

Habitat: Spotted munias inhabit open or semi-open habitats including cultivated and inhabited areas, parks and gardens, rice fields, grasslands, and forest edges.

Diet: The birds eat grass seeds, especially rice, from off of the ground and on live plants. They also eat small berries. Sometimes, they eat dead animals along roadsides. When human trash dumps are available, they are seen removing scraps of food, such as bread, from the area.

Behavior and reproduction: Spotted munias are often found in large flocks of birds of various species. Their call is a series of repeated "kitty-kitty-kitty." Their wide variety of calls is used for keeping in contact with other birds or to express alarm. The soft song is a "klik-klik-klik" followed by a series of whistles and ending with a "weeee." The song has many variations. A breeding colony is often built consisting of hundreds of round nests of grass and tree bark. Females lay three to seven white eggs. The incubation period is about fourteen days.

Spotted munias and people: People often keep and breed spotted munias. Many are caught for eventual sale into the pet business.

Conservation status: Spotted munias are not threatened. There is no noticeable impact on its numbers with respect to many of its numbers being caught as pets, except for those in Vietnam and Southeast Asia, where they are also caught for human consumption and as part of religious ceremonies. ∎

FOR MORE INFORMATION

Books:

del Hoyo, Josep, Andrew Elliott, Jordi Sargatal, Jose Cabot, et al., eds. Handbook of the Birds of the World. Barcelona: Lynx Edicions, 1992.

Dickinson, Edward C., ed. The Howard and Moore Complete Checklist of the Birds of the World, 3rd ed. Princeton, NJ and Oxford, U.K.: Princeton University Press, 2003.

Forshaw, Joseph, ed. Encyclopedia of Birds, 2nd ed. San Diego, CA: Academic Press, 1998.

Harrison, Colin James Oliver. Birds of the World. London and New York: Dorling Kindersley, 1993.

Perrins, Christopher M., and Alex L. A. Middleton, eds. The Encyclopedia of Birds. New York: Facts on File, 1985.