Handbook of Field Methods for Monitoring Landbirds
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United States Department of Agriculture Handbook of Field Methods Forest Service for Monitoring Landbirds Pacific Southwest Research Station General Technical Report PSW-GTR-144-www C. John Ralph Geoffrey R. Geupel Peter Pyle Thomas E. Martin David F. DeSante Ralph, C. John; Geupel, Geoffrey R.; Pyle, Peter; Martin, Thomas E.; DeSante, David F. 1993. Handbook of field methods for monitoring landbirds. Gen. Tech. Rep. PSW-GTR-144-www. Albany, CA: Pacific Southwest Research Station, Forest Service, U.S. Department of Agriculture; 41 p. This handbook is a compilation of methods that can be used to assay population size, demographics, and status of many species of birds occurring in a wide variety of habitats. The handbook will prove useful to field biologists, managers, and scientists anywhere in the New World from the arctic through the tropics. The methods include four types of censuses for determining population size and trends, mist-netting and nest searches to determine demographic parameters, and other methods that will be useful in operating a monitoring station, including habitat and weather observations, and suggestions for training personnel and possibilities for detailed studies. Suggestions of specific methods and data forms are included. Retrieval Terms: bird populations, census, mist-nets, monitoring, nesting birds Acknowledgments: The late L. Richard Mewaldt was the first among equals in setting high standards and maintenance of accurate records. His contributions are detailed by Ralph (1992). We take great pleasure in dedicating this handbook to him. This handbook is a direct outgrowth of the landbird program started more than 25 years ago at the Point Reyes Bird Observatory to monitor landbird populations in coastal California, and much of this handbook is the result of the methods developed and adapted there. Over this period, many people contributed to the development of this landbird monitoring program. The handbook benefitted greatly from discussions and correspondence by Bruce Bingham, Grant Ballard, Danny Bystrak, Barbara Carlson, Brenda Dale, Sam Droege, John Faaborg, Kevin J. Gutzwiller, Denise Hardesty, Kimberly Hollinger, Bill Howe, David W. Johnston, Stephanie Jones, Cherry Keller, Kathy Klimkiewicz, Rolf R. Koford, Karin Kozie, Borja Milá, Sherri Miller, Michael Morrison, Barry R. Noon, Nadav Nur, Raymond J. O’Connor, Will Peach, Carol Pearson Ralph, Martin Raphael, Dan Reinking, Christopher C. Rimmer, Sharon Ritter, John T. Rotenberry, John R. Sauer, Tom Sherry, Sue Sniado, John Tautin, Jared Verner, Dennis Vroman, George E. Wallace, Dan Welsh, and Joseph M. Wunderle, Jr. The Authors: C. John Ralph is a Research Biologist at the Station’s Redwood Sciences Laboratory, 1700 Bayview Drive, Arcata, Calif. 95521. Geoffrey G. Geupel and Peter Pyle are Director of Terrestrial Research Programs and Farallon Biologist, respectively, at the Point Reyes Bird Observatory in Stinson Beach, Calif. Thomas E. Martin is Assistant Unit Leader—Wildlife at the U.S. Fish and Wildlife Service in Fayetteville, Arkansas, and Associate Professor at the University of Arkansas, Fayetteville. David F. DeSante is Executive Director at the Institute for Bird Populations in Point Reyes Station, Calif. Publisher: Pacific Southwest Research Station Albany, California (Mailing address: P.O. Box 245, Berkeley, CA 94701-0245 Telephone: 510-559-6300) May 1993 Handbook of Field Methods for Monitoring Landbirds C. John Ralph Geoffrey R. Geupel Peter Pyle Thomas E. Martin David F. DeSante Contents In Brief .................................................................................................................................................... iii Introduction .............................................................................................................................................. 1 Objectives of a Monitoring Program ............................................................................................... 1 Glossary ............................................................................................................................................ 2 Selecting Monitoring Methods and Locations of Monitoring Stations ............................................. 2 Selection of Methods........................................................................................................................ 2 Selection of a Station Location ........................................................................................................ 4 Permanent Stations ........................................................................................................................... 4 General Monitoring Procedures ............................................................................................................ 4 Species To Be Covered .................................................................................................................... 4 Monitoring Period ............................................................................................................................ 5 Maintenance of a Study Plot ............................................................................................................ 5 Journal Keeping ................................................................................................................................ 6 Training and Numbers of Personnel ................................................................................................ 6 Data To Be Taken ............................................................................................................................ 6 Constant-Effort Mist Nets and Banding ............................................................................................... 7 Scope................................................................................................................................................. 7 Net Placement................................................................................................................................... 7 Net Locations ................................................................................................................................... 8 Erecting and Operating Nets ............................................................................................................ 8 Net Specifications and Maintenance ............................................................................................... 9 Operation of Nets ............................................................................................................................. 9 Removing Birds from Nets ............................................................................................................ 10 Processing ....................................................................................................................................... 12 Special Problems ............................................................................................................................ 12 Data Collection ............................................................................................................................... 12 The Process of Determining the Extent of Skull Pneumatization ................................................14 Data Entry ....................................................................................................................................... 20 Sources of Equipment .................................................................................................................... 22 Bird Banding Laboratory and Office .............................................................................................22 Nest Searches .......................................................................................................................................... 22 Nest Sites ........................................................................................................................................ 23 Nest Monitoring ............................................................................................................................. 25 Filling Out the Forms ..................................................................................................................... 25 Predation Risk from Monitoring .................................................................................................... 28 Vegetation Measurement ............................................................................................................... 28 Censusing ................................................................................................................................................ 29 General Considerations .................................................................................................................. 29 Point Count ..................................................................................................................................... 31 Strip Transects ................................................................................................................................ 35 Area Search .................................................................................................................................... 35 Spot Mapping ................................................................................................................................. 35 Contents Other Considerations ...........................................................................................................................