Evaluation of management techniques for the Spanish imperial eagle

Published source details Ferrer M. & Hiraldo F. (1991) Evaluation of management techniques for the Spanish imperial eagle. Wildlife Society Bulletin, 19, 436-442.
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This study is summarised as evidence for the following.

	Action	Category
	Bury or isolate power lines to reduce incidental bird mortality Action Link
	Add perches to electricity pylons to reduce electrocution Action Link
	Use signs and access restrictions to reduce disturbance at nest sites Action Link
	Remove/treat endoparasites and diseases Action Link
	Foster eggs or chicks of raptors with wild conspecifics Action Link

Bury or isolate power lines to reduce incidental bird mortality

A before-and-after trial in the wetlands of the Doñana National Park (Ferrer & Hiraldo 1991), Andalusia, Spain, found that six-month survival for radio-marked juvenile Spanish imperial eagles Aquila adalberti increased from 18% of 17 individuals in 1986-7 to 80% of 15 in 1988-9 following the isolation or burial of previously identified dangerous power lines. This study discusses other eagle management techniques, described in ‘Add perches to electricity pylons to reduce electrocution’, ‘Use signs and access restrictions to reduce disturbance at nest sites’, ‘Foster eggs or chicks with wild conspecifics’ and ‘Remove/treat endoparasites’.
Add perches to electricity pylons to reduce electrocution

A before-and-after study in a wetland national park in Andalusia, Spain (Ferrer & Hiraldo 1991), found that adding perches to 80 electricity pylons did not reduce electrocution rates of Spanish imperial eagle Aquila adalberti. This study discusses other eagle management techniques, described in ‘Bury or isolate power lines’, ‘Use signs and access restrictions to reduce disturbance at nest sites’, ‘Foster eggs or chicks with wild conspecifics’ and ‘Remove/treat endoparasites’.
Use signs and access restrictions to reduce disturbance at nest sites

A small study in 1976-88 in the wetlands of the Doñana National Park, Andalucia, Spain (Ferrer & Hiraldo 1991), found that there were no differences in number of Spanish imperial eagle Aquila adalberti pairs that laid, clutch size, hatching size or nestling survival after trails near nests were temporarily closed. This study discusses other eagle management techniques, described in ‘Add perches to electricity pylons to reduce electrocution’, ‘Bury or isolate power lines’, ‘Foster eggs or chicks with wild conspecifics’ and ‘Remove/treat endoparasites’.
Remove/treat endoparasites and diseases

A small study in 1976-88 in the wetlands of the Doñana National Park, Spain (Ferrer & Hiraldo 1991) found that survival rates of Spanish imperial eagle Aquila adalberti chicks did not appear to be affected by treating them for Staphylococcus aureus infections (two of 19 untreated chicks died, probably from infections vs. none of the nine treated chicks died before fledging). The authors note that this may be due to the small sample size in the study. This study also discusses other interventions, in ‘Add perches to electricity pylons to reduce electrocution’, ‘Bury or isolate power lines’, ‘Use signs and access restrictions to reduce disturbance at nest sites’ and ‘Foster eggs or chicks with wild conspecifics’.
Foster eggs or chicks of raptors with wild conspecifics

A replicated study in 1977-88 in wetlands in the Doñana National Park, Andalucia, Spain (Ferrer & Hiraldo 1991), found that there were no differences in survival between chicks relocated from nests were siblicide was likely to occur into nests thought to be safer (68% of 19 chicks surviving) compared to unmoved chicks (82% of 77 chicks surviving from all unmanipulated nests and 73% of 18 chicks from broods of three). Twelve of the moved chicks were from within the park and seven were moved in from outside. This study also discusses other interventions, in ‘Add perches to electricity pylons to reduce electrocution’, ‘Bury or isolate power lines’, ‘Use signs and access restrictions to reduce disturbance at nest sites’ and ‘Remove/treat endoparasites’.