Hawaiian Crow (Corvus hawaiiensis)
Justification This species is classified as Critical owing to the tiny size of the single wild population, which has declined extremely rapidly during the 1990s. The captive flock is projected to consist of 10 breeding pairs for the indefinite future, but unless captive-released birds and their offspring can make a contribution to the wild population, this species could shortly become Extinct in the Wild.Identification48 cm. Large crow or small raven. All dark sooty-brown with paler primaries. Heavy, black bill. Brown eyes. Juvenile has blue eyes and pink mouth lining. Voice Huge variety of squawks, screams, growls, and dissonant croaks. Hints Flies high over montane forest and ridges
POPULATION ESTIMATE 3
Range & Population Corvus hawaiiensis is endemic to Hawai`i in the Hawaiian Islands (USA), where it is survives only in the Kona Forest Unit of Hakalau National Wildlife Refuge. In 1992, there were only 11 or 12 birds In October 1999, there were just three birds, including one pair which may no longer be capable of reproduction. Captive breeding started in the 1970s and, by 1998, 24 birds had been released but, during 1997-1998, 18 died and the rest were recaptured to protect them and preserve genetic diversity.
Ecology It inhabits wet `ohi`a-koa forest, scrub and rangelands but is now more or less confined to high mountain forest. It is omnivorous, but primarily feeds on the fruit of native understory plants.
Threats It has suffered from extensive habitat alteration, particularly reduction of understory food-plants as a result of the activities of feral ungulates, logging, agriculture and the loss of pollinators and dispersers. The impact of collecting and shooting has probably also been substantial, even in recent decades. Other documented threats include predation by introduced rats, the small Indian mongoose Herpestes auropunctatus and the native Hawaiian Hawk Buteo solitarius (classified as Near Threatened), and avian malaria and pox carried by introduced mosquitoes. Captive-reared birds have also suffered from disease, with at least one dying from bacterial infection, and diseases may have made others more vulnerable to predation.
Action Captive-raised individuals have been released into managed habitat and monitored3, (stopped in September 1998, following the death of three birds in as many days5). Introduced mammalian predators are trapped in the Kona Forest Unit. Translocation of B. solitarius failed because the birds homed back from over 32 km1. An environmental assessment is in preparation, other potential release-sites have been investigated, and suggestions are under consultation6.
