This article is a US Government work and, as such, is in the public domain in the United States of America.
Version of Record online: 11 MAY 2011
This article is a US Government work and, as such, is in the public domain in the United States of America. Copyright © 2011 The Wildlife Society
The Journal of Wildlife Management
Volume 75, Issue 3, pages 509–512, April 2011
How to Cite
Sauer, J. R., Otto, M. C., Kendall, W. L. and Zimmerman, G. S. (2011), Monitoring bald eagles using lists of nests: Response to Watts and Duerr. The Journal of Wildlife Management, 75: 509–512. doi: 10.1002/jwmg.84
Associate Editor: Marc Bechard.
- Issue online: 11 MAY 2011
- Version of Record online: 11 MAY 2011
- Manuscript Accepted: 16 SEP 2010
- Manuscript Received: 22 DEC 2009
- bald eagle;
- dual frame sampling;
- list frame;
The post-delisting monitoring plan for bald eagles (Haliaeetus leucocephalus) roposed use of a dual-frame sample design, in which sampling of known nest sites in combination with additional area-based sampling is used to estimate total number of nesting bald eagle pairs. Watts and Duerr (2010) used data from repeated observations of bald eagle nests in Virginia, USA to estimate a nest turnover rate and used this rate to simulate decline in number of occupied nests in list nests over time. Results of Watts and Duerr suggest that, given the rates of loss of nests from the list of known nest sites in Virginia, the list information will be of little value to sampling unless lists are constantly updated. Those authors criticize the plan for not placing sufficient emphasis on updating and maintaining lists of bald eagle nests. Watts and Duerr's metric of turnover rate does not distinguish detectability or temporary nonuse of nests from permanent loss of nests and likely overestimates turnover rate. We describe a multi-state capture–recapture model that allows appropriate estimation of rates of loss of nests, and we use the model to estimate rates of loss from a sample of nests from Maine, USA. The post-delisting monitoring plan addresses the need to maintain and update the lists of nests, and we show that dual frame sampling is an effective approach for sampling nesting bald eagle populations. © 2011 The Wildlife Society.