The Present Status of the Birds of Hawaii' ANDREW J. BERGER2 THEGREAT EXPANSES of open ocean that sep­ waii, and in 1962 birds were first released in arate the Hawaiian Islands from the major the Paliku Cabin area of Haleakala Crater on continental land masses of North America and Maui. There is still debate as to whether or Asia resulted in the evolution of a number of not the Nene originally inhabited Maui. unique landbirds. Unfortunately, a higher per­ The Nene was on the verge of extinction in centage of species of birds have become extinct the 1940s, and the species is still included in in Hawaii than in any other region of the the list of endangered species. In 1949 a Nene world. Approximately 40 percent of the en­ Restoration Program was begun by using a pair demic Hawaiian birds are believed to be ex­ of captive birds obtained from Herbert Ship­ tinct, and 25 of the 60 birds in the 1968 list man of Hawaii. This has been a very success­ of "Rare and Endangered Birds of the United ful program, and Nene have been raised in States" are Hawaiian CRare and Endangered captivity both at the Severn Wildfowl Trust Fish and Wildlife of the United States, 1968 at Slimbridge, England, and at the State of edition," Bureau of Sport Fisheries and Wild­ Hawaii Fish and Game rearing station at life, Washington, D. C.). Most of the native Pohakuloa on the Saddle Road of Hawaii birds of Oahu have long been extinct, and few (Elder, 1958) . native landbirds are to be found on any of the The program at Pohakuloa has been increas­ main islands below 3,000 feet elevation. ingly effective throughout the years, primarily . Three general groups of birds are found in through the dedicated efforts of Mr. Ah Fat Hawaii today: endemic, indigenous, and intro­ Lee. Over 500 Nene have been raised at Po­ duced. hakuloa during the period of 1949 through ENDEMIC HAWAIIAN BIRDS 1968. Most of these pen-reared birds have been released at several known habitats of wild Ten families of birds are recognized as hav­ Nene on the slopes of Maun a Loa; a smaller ing endemic genera, species, or subspecies in number have been released in Haleakala Hawaii (although taxonomic dispute still ex­ Crater. ists regarding the relationship of some Ha­ The Nene is a highly specialized goose, waiian forms to closely related North American adapted for living in a rugged habitat of lava forms); in addition, one entire famil y of birds flows far from any standing or running water (Drepanididae) is endemic to the Hawaiian (Miller, 1937). Among the more noticeable chain of islands (Amadon, 1942; Mayr, 1943). anatomical specializations for this terrestrial An "endemic" form is one that occurs in one life is a reduction in the webbing between the region only and is not found in any other toes. The birds spend much of the time on part of the world. Ornithologists believe that sparsely vegetated lava flows on Mauna Loa the ancestors of these birds reached Hawaii and Hualalai, at elevations between approxi­ from the areas indicated in Figure 1. The mately 5,000 and 8,000 feet. Here the birds endemic Hawaiian birds, listed according to often build their nests on the lava although these 11 families, are discussed briefly. typically well concealed in clumps of vegeta­ 1. Anatidae (duck s, geese, and swans) tion. The nests are lined with the birds ' own down feathers ; the clutch consists of from 2 The NENE or HAWAIIAN GOOSE (B rante to 5 eggs. sandvicensis) is endemic to the island of Ha- The KOLOA or HAWAIIAN DUCK (Anas wy­ 1 Manuscript received June 13, 1969. villiana) originally was found on all of the 2 D epartm ent of Zoology, University of H awaii, Honolulu. Supported by NSF Grant GB-5 612. main Hawaiian Islands except Lanai and Ka- 29 I.» o HauiaJlan Th rush. Nene, Owl. Crow. Hawk. Ga l/lnule. Coot. Stilt._Black i ·crowned Night Heron "0 :> n...... ......>-:r:I I . .- I .CHRISTMAS f'"! - > » : ?~ ! , V~ . ~vw 0 n \ - - ) ~ i .,......,· ,... I 1 1i!IPrtrJ/nl. , 1'~:.1 I . I I I _. Ir [fJ n...... tTl " . .Q ... ',-{"- ~"';'.'-'j' · 4 . ' , ,' . •• • ;: t. RAROTONGA, - .~ ~ ., ~ N PITCAIRN ."'" '-< ~ § ~l ~ -< ..... F IG. 1. Map of the Pacific Basin to show regions from which the ancestors of endemic Hawaiian birds are presumed to have originated, The broken \0 -....J arrow indicates the annual migratory flights of the Pacific Golden Plover between Alaska and the Hawaiian Islands, o Birds of Hawaii-BERGER 31 hoolawe. A decline in numbers of Koloa on on Laysan, and, after these operations ceased, most of the islands was noted by several writ­ Japanese feather hunters also used large num­ ers after the turn of the present century, and bers of the ducks for food. Theodore Roose­ in recent years this duck has been found only velt established the Hawaiian Islands National on Kauai. A propagation program is now un­ Wildlife Refuge in 1909, but Alfred M. Bai­ derway at Pohakuloa, Hawaii. ley believed there were only seven ducks left Man probably was the most serious predator by 1912. Alexander Wetmore (1925) counted on the Koloa, and the birds could be hunted 20 birds during the Tanager Expedition of legally during the early 1920s, when the bag 1923. Since that time, when the last of the rab­ limit was 25 ducks per day. Duck hunting bits were believed to have been killed, both was prohibited for a period of two years be­ the vegetation and the Laysan Duck have ginning in 1939, and hunting was further made a remarkable recovery. Because of the closed during World War II. Fortunately, dense vegetation of the areas inhabited by the duck hunting (both for the Koloa and the ducks, it is virtually impossible to make an wintering migratory ducks) has been prohib­ accurate count of the birds, but the population ited since that time. The decline in taro and is now thought to fluctuate between 100 and rice acreages, however, has reduced suitable 600. The downward fluctuations in population habitat for the birds. .that do occur are thought to result in part Wild dogs are known to be serious preda­ from severe winter storms, but there may be tors on both ducklings and the adults in their other, as yet unknown, reasons. The present flightless stage during the annual postnuptial habitat is thought to be adequate for about molt. A number of other animals (e.g., large­ 600 ducks. mouth bass, bullfrog) have been known to It is imperative for the future welfare of the kill small ducklings on Kauai. The role of the Laysan Duck (as well as for the surviving mongoose in the great reduction or extinction honeycreeper and the tens of thousands of of the Koloa throughout most of its former nesting seabirds) that predators (such as rats, range is unknown, but it may be significant cats, dogs) and pest insects and plants (which that Kauai, the last stronghold of the Koloa, . would alter the ecology of the island) be pre­ is the only main island on which the mon­ vented from gaining access to Laysan Island. goose has not been introduced. Wild cats, rats, Nests of the Laysan Duck are built on the and pigs also destroy nests. ground and are well concealed among the vege­ The main breeding season on Kauai appears tation. Little is known about the breeding biol­ to be from December through May, although ogy in the wild, however. There are more than the species seems to breed throughout the year, 150 birds in zoos and private aviaries; breeding inasmuch as nests or downy young have been pairs also are held at Pohakuloa, Hawaii. found in all months except August (Swed­ 2 . Accipitridae (hawks, kites, and eagles): berg, 1967). The well-concealed nests are built on the ground. Clutch size is reported to The HAWAIIAN HAWK or 10 (Buteo soli­ be from 2 to 10 eggs, with a mean of 8.3 tarim), for entirely unknown reasons, has al­ eggs for wild birds. The Koloa is tolerant of ways inhabited Hawaii only. The bird is now varying climatic and ecological conditions. On uncommon and has been placed on the list of Kauai the birds nest from sea level to 3,500 rare and endangered species. The chief reason feet elevation, and in areas of annual rainfall for the decline in numbers of this interesting varying from 35 to 125 inches. bird is believed to be shooting by uninformed people who consider all hawks to be "chicken The LAYSAN DUCK (Anas laysanemis) was hawks." All available evidence, however, sug­ in danger of extinction during the early part gests that rodents form the main food of the of this century (Rothschild, 1893-1900). 10. Although much rarer than the Hawaiian Again man was the agent of destruction. The Owl, the hawk sometimes can be seen soaring birds were hunted for sport and for food by high in the air on the slopes of both Mauna the personnel of the guano mining company Loa and Mauna Kea. 32 PACIFIC SCIENCE, Vol. 24, January 1970 Few nests of this species have been found Several birds survived the long sea voyage to and very little is known of its breeding habits. England in the 1890s. The birds build nests of twigs and sticks in Like many rails on oceanic islands, the Lay­ trees, and one author has described a lining san Rail had evolved into a flightless condition . made of the stems and fronds of ferns . Two The birds ate many kinds of insects, the flesh or three eggs are thought to form a clutch.