HAND-REARING CORVIDS FOR REINTRODUCTION - IMPORTANCE OF FEEDING REGIME, NESTLING GROWTH, AND DOMINANCE

Captive propagation has become increasingly important in preventing ex tinction in many avian species, including the Hawaiian crow (Corvus ha waiiensis) and Mariana crow (C. kubaryi). We used 3 surrogate species, common raven (C. corax), American crow (C. brachyrynchos), and black- billed magpie (Pica pica), to develop captive-rearing protocols for en dangered corvids. Here we; compare the health, growth, and survival am ong nestlings hand-reared on 14 feeding regimes. Frequency of feeding chicks for the first 2 weeks after hatch varied from once every 30 min to once every 2 hr. From 2 weeks until near fledging age, frequency o f feeding varied from once every hour to once every 3 hr. Initial amou nts of food fed varied from unlimited (ad libitum) to a restricted amo unt (a total of 15, 25, or 40% of a chick's body mass). Combinations o f frequent feeding and large amounts of food produced fast-growing, he avy birds with few fault bars in their feathers, but all hand-reared n estlings grew more slowly than wild-reared chicks. Initial amount of f ood offered to day-old chicks affected growth and survival more than f requency of feeding in very large passerines (e.g., common ravens). In small- to medium-sized passerines (e.g., black-billed magpies, Americ an crows), frequency of feeding affected growth and survival more than initial amount of food.