Hawaiian crow (Corvus hawaiiensis)
|Also known as:||Alala|
|Size||Length: 48 – 50 cm (5)|
Classified as Extinct in the Wild (EX) on the IUCN Red List 2004 (2).
Known in Hawaii as Alala (3), this species is the most endangered corvid in the world and is the only crow species found in Hawaii. It is a large, sooty, black crow with brownish primaries. The black bill is stout and slightly upturned, the legs are black and the tail is square at the tip. Both sexes and all ages are similar in appearance, but males are slightly larger than females. This species produces a wide variety of calls including a repeated ‘kerruk, kerruk’ and a loud ‘kraa-a-a-ik’ in flight (5).
This species is endemic to Hawaii, and is currently found in a 260 km² area of central Kona, on a single ranch (3). It was formerly common and bred throughout the slopes of the volcanoes of Hualalai and Mauna Loa (3). By 1987, just ten wild individuals remained (5).
The Hawaiian crow inhabits native Hawaiian Ohia forests or Ohia and Koa mixed forest. It shows a marked preference for open forests (3).
The diet is varied and consists mainly of fruit, but insects and nectar may also be eaten (3). The Hawaiian crow flakes away bark whilst foraging for insects and has also been observed raiding the nests of other bird species. Breeding occurs between March and July (3) - the bulky nests are made of sticks with a cup of soft grasses inside, and are usually located in large trees in isolated stands (5). A clutch can contain between one and five eggs (3). The flight style is strong, and they have been seen tumbling and playing in the air like ravens (5).
Habitat loss and illegal hunting are thought to be the main reasons for the decline of this species. Disease, over-grazing (3) and introduced mammalian predators such as rats, feral cats and mongooses (4) are also likely to have played a part (3). At present, a further threat has arisen as a result of the very low population size. This makes captive breeding more difficult; inbreeding of relatives may be more likely and the gene pool is limited (3). Small populations are also vulnerable to chance events such as severe storms and diseases.
This species is protected by law. A small captive population of ten individuals (1) is held on the island of Maui, and chicks have been successfully raised. Eggs had also been taken from the wild, reared and re-released successfully. In 1994 the population consisted of three wild breeding pairs from a wild population of 8 - 12 individuals, three breeding pairs from the 10 birds held in captivity, and nine captive-reared chicks to be reintroduced to the wild; the total population was therefore estimated to be around 31 birds (1). The wild population is now extinct and only captive held birds remain alive (2).
Authenticated (31/5/02) by Donna Ball, Wildlife Biologist Hakalau Forest National Wildlife Refuge, and Alan Lieberman, Manager of the Keauhou Bird Conservation Center.
- Corvid: of the family Corvidae, crows, jays, magpies, nutcrackers and rooks.
- Endemic: species or taxonomic group which is confined to a particular country or geographic area.
- Primaries: in birds, the outer flight feathers.
IUCN Red List (July, 2014)