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Providing evidence to improve practice

Individual study: Feeding rates and amounts affect hand-reared corvid nestling growth rates and post-release survival

Published source details

Whitmore K.D. & Marzluff J.M. (1998) Hand-Rearing Corvids for Reintroduction: Importance of Feeding Regime, Nestling Growth, and Dominance. The Journal of Wildlife Management, 62, 1460-1479


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Use puppets to increase the survival or growth of hand-reared chicks Bird Conservation

A replicated ex situ study in Idaho, USA (Whitmore & Marzluff 1998), found that the growth of raven Corvus corax chicks did not vary between 30 individuals fed with a puppet and 82 fed by keepers. Post-release survival and reproduction were not compared. This study is also discussed in ‘Artificially incubate and hand-rear birds in captivity’.

 

Artificially incubate and hand-rear songbirds in captivity Bird Conservation

A replicated ex situ study in Idaho, USA (Whitmore & Marzluff 1998), found that hand-reared corvid (ravens Corvus corax, American crows C. brachyrynchos and black-billed magpies Pica pica) chicks fed large amounts of food regularly grew faster and were healthier than those fed less food, or less regularly (e.g. ravens fed 40% of their weight every hour grew the fastest, those fed 15% of their weight grew the slowest; crows fed unlimited amounts every hour grew fastest, those fed every two hours grew the slowest; magpies fed unlimited amounts every 30 minutes grew the fastest). However, no feeding regime allowed chicks to grow as fast as wild-raised birds. Crows and magpies were most affected by feeding frequency, whereas ravens were more influenced by the initial amount of food offered. Survival three months after release was positively related to feeding frequency. Eggs were collected from the wild after 0-18 days of incubation and incubated at 37.5oC (crows and ravens) or 38.0oC (magpies) and at 31-69% humidity. Overall, 72% of 430 eggs hatched. After hatching, chicks were transferred to heated aquaria and fed with minced meat, egg, insects and dog food. This study is also discussed in ‘Use puppets to increase the survival or growth of hand-reared chicks’.