NATURAL HISTORY OF THE SWAINSON'S WARBLER 3 



12:30 p.m. on sunny, windless days. To measure the light in- 

 tensity, I placed a mirror on the ground in the exact spot where a 

 Swainson's Warbler had been feeding less than 1 minute before, 

 held an exposure meter 1 foot above the mirror with the photo- 

 electric cell upward, and took a reading. 



Territory-mapping and transect methods were used in making 

 censuses. Dimensions of territories were determined by spot- 

 mapping males on maps marked off into transects or grids. Stud- 

 ies of territorial behavior were facilitated by color-marking birds 

 of both sexes with celluloid or metal leg bands. Birds were cap- 

 tured with mist nets for marking. 



Birds taken on the breeding and wintering grounds were 

 weighed shortly after capture ; birds taken during migration were 

 weighed after being held in a freezer for various periods of time. 



Measurements are from files in the U.S. National Museum. 

 Time is given as Eastern Standard Time unless otherwise indi- 

 cated. Bird names used in the text are from the A.O.U. Check-list 

 of North American Birds (1957) ; plant names are from Fernald 

 (1950) and Radford, Ahles, and Bell (1964) ; and insect names 

 are from Lutz (1935). 



ACKNOWLEDGEMENTS 



I am grateful to many persons for their contributions to this 

 project. Anna Gilkeson Meanley, my wife, worked with me on 

 several occasions in the Ocmulgee riverbottom canebrakes and in 

 the Great Dismal Swamp. Linda Hall, Lucille F. Stickel, Nancy 

 C. Coon, Paul A. Stewart, and Van T. Harris reviewed the manu- 

 script. Samuel A. Grimes gave me a copy of his superb photograph 

 of a pair of Swainson's Warblers at their nest, and Frederick C. 

 Schmid made several excellent photographs for me. Oliver H. 

 Hewitt of Cornell University presented me with a photograph of 

 John Abbott, and E. Milby Burton of the Charleston Museum gave 

 me permission to use a photograph of the Reverend John Bach- 

 man. The Fogg Art Museum of Harvard University and the 

 Harvard College Library made available a copy of John Abbot's 

 illustration of the Swainson's Warbler. H. L. Stoddard, Sr., and 

 Robert A. Norris of the Tall Timbers Research Station, Talla- 

 hassee, Fla., gave me specimens that struck the TV tower at the 

 station. Eugene P. Odum and William Dopson of the University 

 of Georgia and James B. Cope of Earlham College gave me data 

 from specimens in their collections. J. Fred Denton of Augusta, 

 Ga., and M. G. Vaiden of Rosedale, Miss., provided me with im- 

 portant data from their studies. John W. Aldrich, Gorman M. 



