Individual study: Supplementary feeding after hatching does not increase hatchling survival or fledging success in bald eagles Halieetus leucocephalus in Alaska, USA
Gende S.M. & Willson M.F. (1997) Supplemental feeding experiments of nesting bald eagles in southeastern Alaska. Journal of Field Ornithology, 68, 590-601
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Provide supplementary food for raptors to increase reproductive success
A randomised, replicated, controlled and paired trial in southeast Alaska, USA, in 1994-5 (Gende & Willson 1997), found that bald eagle Halieetus leucocephalus pairs provided with supplementary food did not raise significantly more chicks than control (unfed) pairs and fed chicks were not significantly heavier (average of 2 chicks/nest fledged from 18 fed nests, average weight of 4.0 – 4.4 kg/chick vs. 2 chicks/nest and 4.1 – 4.2 kg/chick for 18 control nests). The authors note that nest failures and brood reductions were rare following hatching in both fed and control pairs, with most losses being during incubation (22 of 60 nests failed before hatching, three nests failed after hatching). Supplementary food consisted of a pink salmon Oncorhynchus gorbuscha provided daily from the date of hatching until hatchlings were seven weeks old, the amount of supplemental food carried to the nests was estimated to provide approximately 50% of the energy requirements of the nestlings.