- Corvus hawaiiensis
Identification
The Hawaiian Crow, Corvus hawaiiensis, also known as ´Alala to the Native Hawaiians, is a species of bird about the size (48-50 cm in length) of the Carrion Crow but with more rounded wings and a much thicker bill. It has soft, brownish-black plumage, with long, bristly throat feathers; the feet, legs and bill are black.
Distribution
The species is now extinct in the wild, and only survives in captive breeding programs on Hawai'i and Maui. Prior to this, the species was recently only found in the central Kona district of Hawai'i. One attempt to reintroduce captive-raised 'alala in Kona was fatal for most of the birds due to predation by 'io and toxiplasmosis. There are efforts to restore forests in Kona for future reintroduction of the 'alala, including the reintroduction and protection of food plants, if the breeding programs can produce enough birds. The captive-raised birds will need to be numerous and carefully raised to be viable in the wild, as the 'alala lived in large flocks which depended on cooperation and learning within the flock to survive. Fossil remains indicate that it previously occurred in relative abundance on all the main islands, along with two other extinct crow species. The reasons for its extinction are not fully understood. It is thought that habitat alteration, including loss of food plant species, and possibly introduced disease was probably a significant factor in the species' decline. The 'alala was also shot as a nuisance bird for many years.
Taxonomy
Habitat
Behaviour
In the wild, Hawaiian Crows consumed a varied diet, including carrion, eggs and nestlings, other small creatures, fruits, and even human food and scraps. The birds were also known to pry bark off trees to uncover the insects beneath. The birds always nest in trees, with both males and females participating in nest construction. Nests in the wild were typically located in open woodland among a tangle of tree creepers, sometimes well away from other trees. Females generally lay five eggs; the eggs may be incubated by either parent, with the other bird usually sitting quietly near its brooding mate. Hawaiian Crows have a call variously described as a two-toned caw and as a screech with lower tones added, similar to a cat's meow. They also make a ca-wak sound and a complex, burbling song. The last two known wild individuals of this species disappeared in 2002; the species is now classified as Extinct in the Wild. While some individuals remain in captive breeding facilities, attempts to reintroduce captive-bred birds into the wild have been hampered by predation by the Hawaiian hawk or io, which is itself listed as endangered. The small number of living individuals may mean that the gene pool has been reduced to the point that the species can no longer recover.
