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Interannual Golden Eagle (Aquila chrysaetos) Nest-Use Patterns in Central Utah: Implications for Long-Term Nest Protection

Author:
Slater, Steven J., Keller, Kent R., Knight, Robert N.
Source:
The Journal of raptor research 2017 v.51 no.2 pp. 129-135
ISSN:
0892-1016
Subject:
Aquila chrysaetos, breeding season, data collection, eagles, guidelines, land management, managers, nesting, Idaho, Utah
Abstract:
Land managers regularly use temporal nest protections to reduce the likelihood of raptor nest disturbance or abandonment, but guidelines are not consistent across management boundaries. We assessed alternative nest use (i.e., egg-laying) and nest spacing at 28 Golden Eagle (Aquila chrysaetos) territories that were monitored ≥25 yr between 1976 and 2013 (all except seven territories were monitored annually without interruption). Territories contained 1–8 nests (x¯ = 2.9), and average spacing between alternative nests was 0.5 km. Inspection of 21 territories monitored for 26–38 yr without interruption suggested eagles used individual nests an average of every 3.3 yr, laid eggs in any nest within territories an average of every 1.8 yr, and switched nests between 43.3% of consecutive nesting attempts (i.e., egg-laying in discrete breeding seasons). Protecting individual nests for 7 yr, or protecting all nests within a territory for 4 yr after the last documented use of any nest when alternative nests were considered would have protected >90% of all consecutive nesting attempts. These temporal protections are longer than individual nest protections commonly applied by land management agencies (e.g., 3 yr since last use), but shorter than those suggested by Golden Eagle data collected in southwestern Idaho in an area with more alternative nests per territory. We recommend that land managers take a territory approach to Golden Eagle nesting protection, including consideration of local alternative nest-use patterns when possible. Management decisions should be based on the last use of any nest within a territory, including all potential eagle nests within a biologically meaningful distance of one another (e.g., based on local alternative nest spacing) when nest-monitoring data are limited; longer protections should be applied when knowledge of alternative nests is likely incomplete.
Agid:
5977434