HAWAIIAN HONEYCREEPERS: Drepanididae

PHYSICAL CHARACTERISTICS

Hawaiian honeycreepers are a group of birds with very unique appearances. The Drepanididae family is divided into three groups: Hawaiian finches, seed-eaters with thick finch-like bills and songs similar to the cardueline finches; Hawaiian creepers and relatives, including nukupuu, generally green-plumaged (feathered) birds with thin bills that feed on nectar and insects; and mamos, iiwis, and relatives, red plumaged birds that feed on nectar and sing songs of squeaks and whistles.

Hawaiian honeycreepers are small- to medium-sized birds that are often mistaken for finches. They have a compact body and a relatively straight to greatly curved bill, with the wide variation of bill sizes and shapes due to the type of food eaten (some have finch-like bills adapted to feeding on seed pods, while many others have pointed or curved bills in order to forage (search for food) for insects and nectar). They have nine large primary feathers on each wing (with a tenth primary feather that no longer functions and has mostly disappeared), and a tube-like tongue (in most species) with a fringed tip that is adapted to nectar feeding. Plumage comes in a wide variety of colors from dull olive green to brilliant yellow, crimson, and multi-colors. Male Hawaiian honeycreepers are often more brightly colored than females.

GEOGRAPHIC RANGE

Hawaiian honeycreepers are found only on the Hawaiian Islands. They are believed to have descended from a single species of cardueline finch that came to the Hawaiian Islands (it is believed) about three to four million years ago.

HABITAT

Most Hawaiian honeycreepers live in forests, which range from mostly dry to very wet (tropical and semi-tropical) climates. A few species live on small, treeless islets (small islands).

DIET

Hawaiian honeycreepers eat almost anything that is edible. They commonly eat nectar, insects, spiders, slugs, land snails, fruits, seeds and seed pods, tree sap, seabird eggs, and carrion (decaying animals). The flowers of the native plant Metrosideros polymorpha are especially liked by a number of nectar-eating Hawaiian honeycreepers.

BEHAVIOR AND REPRODUCTION

All Hawaiian honeycreepers are diurnal (active during the day). They forage mostly alone and in family groups, but some species feed in mixed flocks. Breeding pairs form strong bonds, and such pairings result in monogamous (having one mate) behaviors for most species. They have a wide range of calls and songs, sometimes described as canary-like. Songs and calls vary sometimes even within a species. Territories for nesting and feeding are often defended aggressively by some species. Other species tolerate visitors into their area. Territories are 1.0 to 1.5 acres (0.4 to 1.0 hectare) in area. Breeding takes place usually from May through July but can go from January to August. The mating pair builds a simple, open cup-shaped nest of grasses, twigs, lichens, rootlets, and other plant materials that is lined with fine fibers and found usually on tree branches. Hatchlings (newborn birds) are born naked, blind, and helpless. Only the female incubates (sits on) the young, but the male feeds the brooding female (mother-bird that gives birth and raises her young) and the young.

HUNTING RED FEATHERS OF APAPANES

Apapanes were captured by early Hawaiian natives in order to pluck some of their feathers for use in various cultural purposes. Expert hunters mixed a sticky paste made from the sap of the breadfruit tree, applied it on tree limbs, and then caught the stuck birds (who were attracted to the sap) with nooses, fiber nets, or their bare hands. Only a feather or two was taken, so the birds were often released if the bird was too small to eat. The feathers would eventually grow back.

HAWAIIAN HONEYCREEPERS AND PEOPLE

Hawaiian honeycreepers pollinate (fertilize) native plants and keep the insect population under control, much to the benefit of people. They also attract tourists to Hawaii who enjoy watching the colorful birds.

CONSERVATION STATUS

Seven species are listed as Critically Endangered, facing an extremely high risk of extinction; five are Endangered, facing a very high risk of extinction; and three are Vulnerable, facing a high risk of extinction. Sixteen species of Hawaiian honeycreeper have become extinct in the recent past, mostly since the arrival of the Polynesians who introduced rats, and later other species of rodents and the mongoose. All species have been hurt, and continue to be hurt, by various degrees with respect to loss of habitat, introduction of diseases, and invasion of introduced predators, animals that hunt them for food. Many conservation programs are currently under way to protect most of the species.

APAPANE (Himatione sanguinea): SPECIES ACCOUNTS

Physical characteristics: Apapanes have bright crimson plumage, along with black wings and tails, a white undertail and abdomen, and a long, down-curved bill. They are about 5.25 inches (13.3 centimeters) long and weigh between 0.50 and 0.56 ounces (14 and 16 grams).

Geographic range: Apapanes are found in ohia lehua rainforests (forests that contain ohia lehua trees) of Hawaii. They commonly range in forested areas over 3,300 feet (1,000 meters) in elevation on Hawaii, Oahu, and Kauai. They are vary rare or extinct on Lanai and Molokai.

Habitat: They inhabit forests over 3,300 feet (1,000 meters) in elevation.

Diet: Nectar makes up the main part of the diet of the apapane species, which is found on the flowering ohia trees. They also feed on insects that are found close to these flowering trees. The birds fly between forest patches of the trees, finding ones that are blooming. Apapanes feed in large flocks of the species, numbering as many as 3,000 individuals per 0.4 square miles (1 square meters) of area.

Behavior and reproduction: The social birds gather in large flocks and fly about forests in search of blooming ohia trees. Their calls include whistles, squeaks, raspings, clickings, and trillings. Their blunt wing tips make loud and distinctive noises while flying. They breed throughout the year, but primarily from February to June, which is the months where ohia nectar is most available.

Apapanes and people: There is no known significant relationship between people and apapanes. Early Hawaiian natives used the red feathers of the apapanes for their feather capes, kahilis (works of art), and helmets.

Conservation status: Apapane are not threatened. They are the most abundant species of Hawaiian honeycreeper. ∎

LAYSAN FINCH (Psittirostra cantans): SPECIES ACCOUNTS

Physical characteristics: Laysan finches have a large parrot-like (heavy, hooked) bill with the tip of the upper mandible (top part of a bird's bill) forming a tiny downward hook. Adult males have a bright yellow head, throat, and breast, and a gray collar around the neck. They have a grayish brown lower back and rump, and a whitish abdomen. Females are less colorful, with dark streaks in a yellowish crown, a gray collar, a yellowish throat and breast, some streaking on the flanks, and dark brown spots along the back. They are 6.0 to 6.5 inches (15 to 18 centimeters) long.

Geographic range: They are found on Laysan Island in the northwestern Hawaiian Island chain. A small population, which was introduced, exists on Pearl and Hermes Reef (a coral atoll). Both locations are part of a long series of islets northwest of the main Hawaiian Islands.

Habitat: Laysan is a low-lying, sandy island about 1,000 acres (405 hectares) in area that contains no trees but plenty of shrubbery and grasses. Pearl and Hermes Reef is a coral atoll containing several small islands.

Diet: Laysan finches are omnivorous (eating both animals and plants), eating such foods as carrion (decaying animals), various invertebrates (animals without a backbone) such as insects, roots, sprouts, soft parts of plants and seeds, and seabird eggs (including the interiors of tern eggs). With respect to tern eggs, Laysan finches puncture their eggshells with its bill in order to get to the food inside.

Behavior and reproduction: Laysan finches are lively and sociable birds. They are very curious and have no fear of humans, often even letting people to feed them from their hands. Males gather at the start of the breeding season in order to make courting displays toward females. Their song is a complex, canary-like warbling. They make cup-shaped nests from grasses and twigs and place them in clumps of grass or in small bushes.

Laysan finches and people: Wildlife biologists have made strong efforts to preserve the species, and to study the evolution of the species.

Conservation status: Laysan finches are listed as Endangered by the U.S. Fish and Wildlife Service (USFWS) and the State of Hawaii, and as Vulnerable by the World Conservation Union (IUCN). They are often injured or killed by violent storms and the increasing numbers of introduced species of animals that compete with them on their limited habitat. ∎

FOR MORE INFORMATION

Books:

Alsop, Fred J. III. Birds of North America. New York: Dorling Kindersley, 2001.

Baughman, Mel M., ed. Reference Atlas to the Birds of North America. Washington, DC: National Geographic, 2003.

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.

Field Guide to the Birds of North America, 4th ed. Washington, DC: National Geographic Society, 2002.

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.

Kaufman, Kenn, with collaboration of Rick and Nora Bowers and Lynn Hassler Kaufman. Birds of North America. New York: Houghton Mifflin, 2000.

Sibley, David. The Sibley Guide to Birds. New York: Alfred A. Knopf, 2000.

Terres, John K. The Audubon Society Encyclopedia of North American Birds. New York: Knopf, 1980.

Web sites:

"Hawaiian Honeycreepers: Family Drepanididae." Southwestern Adventist University, Department of Biology, Keene, Texas. http://biology.swau.edu/faculty/petr/ftphotos/hawaii/postcards/birds/ (accessed on July 20, 2004).