FALSE SUNBIRDS AND ASITIES: Philepittidae

PHYSICAL CHARACTERISTICS

Asities are very small, compact birds with tails so short that individuals look almost spherical, ball-shaped. The velvet and Schlegel's asities grow up to 6 inches (15 centimeters) long and weigh up to 1.5 ounces (40 grams). The common and yellow-bellied sunbird-asities (also called false sunbirds) are smaller, up to 4 inches (10 centimeters) long and up to 0.88 ounces (25 grams) in weight. Both of these species have long, thin, downcurved beaks, like those of nectar-feeding birds. The two asity species have more modest, short, slightly downcurved beaks.

Males sprout brilliant, colorful plumage (feathers) and caruncles (KAR-un-kulz; wart-like skin bumps) at the beginning of the mating season (October through February). After the breeding season, the males revert to duller coloration. Females do not change colors and their colorations are more drab, being various mixtures and patterns of olives, grays, dull greens and dull yellows. The coloration of males outside the breeding season resembles that of the females of the same species, and the caruncles fade and disappear.

GEOGRAPHIC RANGE

These species live in Madagascar, along the east coast and in the sambirano region, another rainforested area in the northwest.

HABITAT

Asities inhabit lowland (sea level), mid-altitude and high altitude tropical primary (original) and secondary (regrown) rainforest, and higher altitude scrub forest (forest with low trees and shrubs). All four species are common and in some areas, plentiful, but since they spend much time in the upper reaches of forests, and because of their small size, asities are difficult to spot and observe.

The velvet asity inhabits most of the east coast of Madagascar, in tropical primary and secondary rain forest from sea level to 5,700 feet (1,900 meters) above sea level. Schlegel's asity lives in tropical deciduous forest in northwestern and western Madagascar. The common sunbird asity lives in the mountainous tropical rainforest belt along most of the east coast, between 1,200 and 4,350 feet (400 to 1,450 meters) above sea level. The yellow-bellied sunbird asity lives in mossy mountain scrub forest that fringes the east coast forest belt between 3,630 and 5,970 feet (1,210 and 1,990 meters) of altitude.

DIET

Asities eat nectar, fruits, insects, spiders, and other small creatures.

BEHAVIOR AND REPRODUCTION

Asities are energetic, lively birds that seem to have little fear of anything around them, including humankind. Some will approach within a few feet of a human being, show a few quick threat displays, then fly off.

Philepittidae singing is simple and not especially loud. Male birds, in flight, can also make fairly loud whirring sounds with their wings. The tenth primary feather of each wing is pointed, and the extended shape creates the sound during flight. A male asity, by adjusting the position of the tenth primary feather, can turn the whirring sound on and off as he wants to. Males use the noise in courtship and defense displays.

Mating behavior in asities is centered on a social behavior system called a polygynous (puh-LIH-juh-nus) lek. One to five males display on vertical branches in an open area twenty to thirty meters across. The males go through several ritualistic displays, competing with others in the lek for the attention and approval of the females. In the most distinctive display, a male will bob up and down on its legs, feet still gripping the branch, while quickly opening and closing the wings. Females gather to watch the displays, each female choosing a male mating partner based on how attracted she is by his courting displays.

In the velvet asity, only females build nests and breeding partners do not form pair-bonds. The other species do establish pair-bonds, and males and females share nest building. A female or breeding pair builds a distinctive, spindle-shaped nest, made from moss, spider webs and plant fibers, suspended from a lower tree branch. The nest, which takes ten or more days to build, is about 10 inches (25 centimeters) in height and 5 inches (12 centimeters) wide. The female lays up to three eggs.

FALSE SUNBIRDS, ASITIES, AND PEOPLE

Asities are not considered pests in any way, since they stay in rainforest and have no interest in human cultivated crops. The tiny, brilliant birds have become a ecotourist draw, especially for dedicated birdwatchers eager to check out Madagascar's unique avian species.

CONSERVATION STATUS

The World Conservation Union (IUCN) lists the yellow-bellied sunbird-asity as Endangered, facing a very high risk of extinction, and Schlegel's asity as Near Threatened, in danger of becoming threatened with extinction. The Endangered designation for the yellow-bellied sunbird-asity may be based on old data in which the species was believed to inhabit only a few mountain forest areas. According to a recent article by Prum and Razafindratsita, more recent surveys have found the yellow-bellied sunbird-asity to be widely distributed and plentiful throughout mountain forests along most of the east coast of Madagascar, and all four species of asity to be plentiful in their ranges and in no danger of extinction. The common sunbird-asity has been found in densities of a thousand individuals per 0.4 square miles (1 square kilometer). Yellow-bellied asities have been recorded in densities of over 2,600 individuals per 0.4 square miles (1 square kilometer).

COMMON SUNBIRD-ASITY (Neodrepanis coruscans): SPECIES ACCOUNT

Physical characteristics: Adult body length is about 4 inches (10 centimeters) and adult weight is 0.88 ounces (25 grams). The breeding-season male's coloration is black fringed with royal blue on the crown, nape and shoulders, with yellow fringing of some of the wing feathers, deep yellow on the ventral surface (undersides) with olive-brown streaks on the breast. The caruncles are squarish and turquoise blue except for green closest to the eye. Females have dull yellowish underparts, yellow on the sides and on the underside of the tail, dull blue-green brown upper bodies and heads.

Geographic range: They are found along the east coast of Madagascar.

Habitat: Sunbird-asities live in the east coast mid-altitude mountain rainforest from 1,200 to 4,350 feet (400 to 1,450 meters) above sea level.

Diet: Common sunbird-asities eat nectar from many plant sources; and insects and related creatures. Common sunbird asities glean (pluck off) insect prey from flowers, leaves, and bark.

Behavior and reproduction: The typical call of the common sunbird-asity is a high-pitched string of notes that sounds like "see-see-see-see-see-see." The call can be heard from 150 to 300 feet (50 to 100 meters) away. Male common sunbird-asities, curiosity-driven, will often approach to within a few feet of a human being.

Common sunbird asities and people: There is little if any direct interaction between common sunbird asities and humanity, except for mostly foreign bird watchers, who benefit ecotourism in Madagascar and contribute to the local and national economies.

Conservation status: These birds are plentiful and widespread along Madagascar's east coast, with densities of a thousand individuals per 0.4 square miles (1 square kilometer) reported. They are not considered endangered or threatened. ∎

FOR MORE INFORMATION

Books:

Goodman, Steven M., and Jonathan P. Benstead, eds. The Natural History of Madagascar. Chicago: University of Chicago Press, 2003.

Lambert, Frank, and Martin Woodcock. Pittas, Broadbills, and Asities. Sussex, U.K.: Pica Press, 1996.

Morris, P., and F. Hawkins. Birds of Madagascar: A Photographic Guide. New Haven, CT: Yale University Press, 1998.

Safford, R. J. and J. W. Duckworth, eds. A Wildlife Survey of Marojejy Reserve, Madagascar. Study Report No. 40. Cambridge, U.K.: International Council for Bird Preservation, 1990.

Periodicals:

Andrianarimisa, A. "A Record of the Sunbird Asity Neodrepanis coruscans in the Rèserve Spèciale d'Ambohitantely." Newsletter of the Working Group on Birds in the Madagascar Region 5, no. 2 (1995): 8–9.

Goodman, S. M., and M. S. Putnam. "The Birds of the Eastern Slope of the Reserve Naturalle Intégrale d'Andringitra." Fieldiana: Zoology, new series no. 85 (1996).

Hawkins, F., R. Safford, W. Duckworth, and M. Evans. "Field Identification and Status of the Sunbird Asities Neodrepanis of Madagascar." Bulletin of the African Bird Club 4 (1997): 36–41.

Prum, R. O. "Phylogeny, Biogeography, and Evolution of the Broadbills (Eurylaimidae) and Asities (Philepittidae) Based on Morphology." Auk 110 (1993): 304–324.

Prum, R. O., and V. R. Razafindratsita. "Lek Behavior and Natural History of the Velvet Asity Philepitta castenea." Wilson Bulletin 109, no. 3 (1997): 371–392.