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Article
Wintering Bald Eagle Count Trends in the Conterminous United States, 1986-2010
Journal of Raptor Research
  • Wade L. Eakle, U.S. Army Corps of Engineers
  • Laura Bond, Boise State University
  • Mark R. Fuller, Boise State University
  • Richard A. Fischer, U.S. Army Engineer Research and Development Center
  • Karen Steenhof, Owyhee Desert Studies
Document Type
Article
Publication Date
9-1-2015
Abstract

We analyzed counts from the annual Midwinter Bald Eagle Survey to examine state, regional, and national trends in counts of wintering Bald Eagles (Haliaeetus leucocephalus) within the conterminous 48 United States from 1986 to 2010. Using hierarchical mixed model methods, we report trends in counts from 11 729 surveys along 844 routes in 44 states. Nationwide Bald Eagle counts increased 0.6% per yr over the 25-yr period, compared to an estimate of 1.9% per yr from 1986 to 2000. Trend estimates for Bald Eagles were significant (P ≤ 0.05) and positive in the northeastern and northwestern U.S. (3.9% and 1.1%, respectively), while trend estimates for Bald Eagles were negative (P ≤ 0.05) in the southwestern U.S. (-2.2%). After accounting for potential biases resulting from temporal and regional differences in surveys, we believe trends reflect post-DDT recovery and subsequent early effects of density-dependent population regulation.

Copyright Statement

This document was originally published by Raptor Research Foundation in Journal of Raptor Research. Copyright restrictions may apply. doi: 10.3356/JRR-14-86.1.

Citation Information
Wade L. Eakle, Laura Bond, Mark R. Fuller, Richard A. Fischer, et al.. "Wintering Bald Eagle Count Trends in the Conterminous United States, 1986-2010" Journal of Raptor Research (2015)
Available at: http://works.bepress.com/laura-bond/12/