Behavioral ecology of bald eagles along the northwest coast: a landscape perspective. [Haliaeetus leucocephalus]
Much of the range of the bald eagle (Haliaeetus leucocephalus) has been subjected to anthropogenic disturbance of greater magnitude than the natural regimes of pre-European settlement times. Consequently, many eagle populations are depauperate. Eagle populations are large and stable, however, along the relatively pristine Pacific Northwest Coast of North America. This study examines: (1) the behavior and ecology of bald eagles along the northwest coast; and (2) the effects of environmental disturbance and resource dynamics on the ecology and evolution of eagles. The ephemeral nature of food supplies along the northwest coast apparently results in eagles being limited primarily by food stress. The foraging behavior of eagles was analyzed using evolutionary game theory as a theoretical construct. Productivity was found to be variable and generally declining in southeast Alaska. Eagles maximized energy input for survival by feeding opportunistically, making broad-scale movements to find food patches, locating food within a patch by searching for prey or for conspecifics with prey, assessing prey profitability, acquiring food by hunting and stealing, and by defending food through threat displays or fighting. Eagles obtain food for reproduction by defending feeding territories and by storing food in their nests. These strategies and adaptations translate up scale and influence characteristics of the regional population. 34 figs., 21 tabs.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6197289
- Report Number(s):
- ORNL/TM-9683; ON: DE86007081
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products. Original copy available until stock is exhausted. Environmental Sciences Division Publication No. 2548
- Country of Publication:
- United States
- Language:
- English
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