Bald Eagle Nest Survey Lake Clark National Park and Preserve, Alaska
Witter LA and Mangipane BM. 2011. Bald Eagle Nest Survey Lake Clark National Park and Preserve, Alaska. Natural Resource Data Series. NPS/LACL/NRDS—2011/313. National Park Service, Natural Resource Stewardship and Science. Fort Collins, Colorado
Nest occupancy and reproductive success of the large breeding populations of bald eagles (Haliaeetus leucocephalus) within parks in the Southwest Alaska Network (SWAN), including Lake Clark National Park & Preserve (LACL), have been selected as a “vital sign” for monitoring as they are indicative of the health of both freshwater and marine ecosystems. Records of nesting activity have been collected regularly in LACL since 1992. Objectives of ongoing eagle monitoring in LACL are to (1) obtain baseline data on population status, and (2) monitor long-term changes in reproductive rates. An additional objective for the 2011 study was to summarize historic LACL bald eagle nesting data. We completed an initial aerial survey in May 2011 to determine nest occupancy, and a follow-up survey in early August to assess productivity. Of the 40 nests found in the interior during the 2011 occupancy survey, 25 (63%) were active. Along the coast, 63% (27 of 43 nests) were active. We revisited 48 of the 52 active nests during productivity surveys. Coastal nests had lower nest success, but higher mean productivity (42% success; 0.77 ± 0.19 SE chicks per active nest) than interior nests (55%; 0.73 ± 0.16). Bald eagle productivity rates exhibited considerable annual variability in LACL since 1992. Efforts should be put forth to determine the causes of this variation as changes in productivity trends over time may indicate attention needs to be paid to broader natural or human-caused changes occurring within LACL ecosystems.
- Type
- Published Report
- Authors
- Witter, Leslie; Mangipane, Buck
- Date of Issue
- 2011-10
- Publisher
- National Park Service, Natural Resource Stewardship and Science
- Units
- LACL , NRSS , SWAN