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U.S. GEOLOGICAL SURVEY
Open-File Report 2007-1212

Interim Summary: Nesting Counts of Ospreys and Brown Pelicans in Northwestern Mexico, 2006

By Charles J. Henny and Daniel W. Anderson

Abstract

The distribution and abundance of nesting populations of California brown pelicans (Pelecanus occidentalis californicus) and ospreys (Pandion haliaetus) were documented in 2006 in northwestern Mexico. For ospreys only, the 2006 data were compared to population estimates from two previous surveys (one conducted in 1977 and another conducted in the period 1992-1993). Overall, the total osprey nesting population increased from 1977 to 1992-1993 and then only changed slightly by 2006, but included regions with localized declines, increases, and stable populations. Preliminary population estimates for California brown pelicans suggest a large and apparently healthy breeding population.

Contents

Abstract
Problem Statement and Implications
Objectives
Methods and Study Area
Study Methods
Results and Discussion
Acknowledgments
References
Appendix

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Send questions or comments about this report to the authors, Charles J. Henny, (541) 757-4840, Daniel W. Anderson, (503)752-2108.

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