852 U.S. NATIONAL MUSEUM BULLETEN 23 7 part 2 



especially within the impoundments. I began a special study of the 

 bird in 1961, primarily to discover the causes of its decline so that 

 remedial action might be taken to prevent its extinction. Many of 

 the observations presented here have resulted from this study. For 

 information on the status of the duskies during the several decades 

 preceding the impoundments, I have quoted freely and at some length 

 from notes sent to the editor of the Lije Histories by the late Donald 

 J. Nicholson of Orlando. 



Spring. — A few birds are present in the marshes all winter, but 

 more seem to appear in late February and early March. The males 

 usually start to sing during the first or second week of March, and at 

 first are heard only in the early morning or at dusk. Their singing 

 increases as the season progresses and soon, especially in calm, cloudy 

 weather, the song may be heard throughout the day. A spring shower 

 increases the males' ardor and activity tremendously. Nicholson 

 (MS.) thus describes the marshes at such a time: 



"Upon entering their habitat one sees individuals on all sides. 

 They seem to appear from nowhere, perch a few moments on the tops 

 of the vegetation, and scold continuously. Here and there males 

 chase the females in zigzag courses, flying low and very swiftly just 

 above the grass tops, sometimes for several hundred yards or more. 

 Others from many directions simultaneously sing their rasping, far- 

 carrying songs from prominent perches atop grass or rush stems. 

 Here and there an exuberant male performs his courtship song flight. 

 Bubbling over with his jerky, rasping, erratic song he flutters slowly 

 almost straight upward to a height of 20 or 30 feet, pauses a moment 

 at the apex, and then, still singing, descends just as slowly to perch in 

 the grass tops again." 



Territory. — The dusky tends, as do other seasides, to nest in rather 

 loose colonies. Each male establishes and defends a definite nesting 

 territory, which seems to vary in size according to its location in the 

 marsh. The region immediately around the nest is most exclusive, 

 and only one pair of birds is ever found inhabiting it. Birds in the 

 center of the marsh seem to defend a roughly circular territory about 

 100 yards in diameter, depending on the vegetation. When the circle 

 includes one of the dikes, where the birds are often seen feeding, the 

 male defends the entire area, including the dike. Birds with nests 

 well back in the marsh are often seen flying 200 yards or more over 

 imsuitable habitat to feeding areas in the tidal zone. The males 

 sometimes sing in such a feeding area, but do not seem to defend it. 



The sizes of individual territories seem to have increased in recent 

 years. Nicholson (MS.) states that in the 1930's he often encountered 

 as many as 20 or 25 sparrows within 100 feet of marsh, and found 

 occupied nests within 40 feet of one another. The birds are certainly 



