Dispersing widely around the world, crows (Corvidae) have colonized even the most isolated of archipelagoes, the Hawaiian Islands. Here at least 5 species of crows evolved, a remarkable degree of speciation given the limited land area of the island chain. Corvid fossils have been discovered on 4 of the 6 largest islands, and the Hawaiian Crow (from hereon called the ‘Alalä) and 2 other species inhabited Hawai‘i Island, the largest of all. ‘Alalä may once have occurred on more than one island, but it was found only on Hawai‘i Island when naturalists first collected it (James and Olson 1991).
Among corvids worldwide, the ‘Alalä is notable for its precipitous decline in range and numbers, strong association with forest habitat, largely frugivorous diet, and remarkable vocal repertoire. It is the largest and one of the most charismatic, culturally significant Hawaiian forest birds, and, as such, major effort and resources are devoted to its recovery.
The ‘Alalä forages to some degree in modified habitats and agricultural settings, as do many other corvids, but it is primarily a forest and woodland bird. It occurred historically throughout dry and seasonally wet forests from low to high elevations on Hualälai Volcano and the western and southeastern slopes of Mauna Loa Volcano. It is one of the most arboreal of crows but sometimes forages on the ground. The ‘Alalä feeds largely on invertebrates and fruits but also on bird eggs and nestlings and limited amounts of nectar and plant parts.
Although the ‘Alalä survived human colonization of the islands, beginning about 1,600 years ago, it is besieged by formidable threats and is one of the most highly threatened species in the world. In 2002, the last wild individuals, a single pair, occupied less than 20 square kilometers of habitat on the western slope of Mauna Loa. Fledglings have not been produced in the wild since 1992, and eggs have not been produced since 1996, despite annual nesting activity. Productivity within the captive flock (35 birds in 2002, not including hatch-year young) has been relatively low and unreliable since 1973, when these birds were first captured for propagation. Birds released to the wild from 1993 to 1996 died or were recaptured, and none reproduced. The ‘Alalä cannot be recovered without dramatically improving habitat conditions and captive propagation.
As in many cultures around the world that paid homage to various species of crows and ravens, Hawaiians regarded the ‘Alalä highly among birds. Its feathers were used ceremonially (Brigham 1899, Munro 1944a), and it is still acknowledged by some as a family or personal god (‘aumakua). When Captain James Cook arrived in the islands in 1778, he was warned not to disturb 2 tame ‘Alalä in the village of Ka‘awaloa, and he was unsuccessful in purchasing them as specimens (Cook and King 1784). After the ascendancy of Western culture, many ‘Alalä were said to have been shot by farmers (Munro 1944a). Widespread alteration and destruction of habitat, reduction of food resources, and introduced diseases and predators ultimately led to the decline of the species (Giffin et al. 1987, Duckworth et al. 1992).
Despite this species' once being relatively common, the first nest and eggs were not described until 1971 (Tomich 1971a). In fact, most of what is known about ‘Alalä is based on studies conducted since 1968 on scattered, relict populations. Some additional information from captive birds is available, but we will never know how wild birds lived and behaved when they occurred in their full numbers in habitats that were unmodified by ancient or more recent cultures.