632 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



Aretas A. Saunders (MS.) sends tlie following: "The song of 

 Wilson's warbler is mainly a series of rapid cliatterlike notes, drop- 

 ping downward in pitch toward the end. It is not especially musical 

 in quality. The notes are short, staccato, and with marked explosive 

 consonant sounds. I have had opportunity to record only songs heard 

 on migration, and since the song is not often heard then, I have only 

 12 records. These have from 8 to 15 notes, averaging about 10. They 

 vary from F'" to C"" in pitch, and from 1% to 1% seconds in length. 

 Individual songs have a pitch range from one to two and a half 

 tones, averaging about one and a half. In most of the records the 

 notes are all on the same pitch and of equal length at the beginning, 

 only the last 3 or 4 notes dropping in pitch, and sometimes becoming 

 faster in time. In all but 2 records the last note is lowest in pitch, 

 and in these exceptions it is the next to the last note that is lowest. 

 A typical song would sound like witititititititatoo.'''' 



Ralph Hoffmann (1899) reports: "On the 2d of November I found 

 a female Wilson's Blackcap in Belmont [Mass.] ; the bird stayed in 

 the same locality till Nov. 20, and uttered when startled a curious 

 wren-like keh^heh^ which I have never before heard." 



Field marks. — Although the identification points in the plumage 

 of Wilson's warbler are mostly negative — absence of wing bars and 

 tail spots, and no streaks or lines in the plumage — the tiny bird is 

 distinctive in the field. The black skull cap is often difficult to see, but 

 the contrast between the plain darkish back and the brilliant, plain 

 under parts is an aid in identification, and even more helpful is the 

 unmarked, bright yellow side of the head with the black eye, a dot 

 in the center. 



Enemies. — Wilson's warbler presumably has few enemies aside from 

 danger during its long migration and the hazards of a ground nest. 

 Wilson's warbler, like the Tennessee and yellow palm, is apparently 

 rarely molested by the cowbird. The three species breed in the same 

 environment, often in the same swamps, where, it may be supposed, 

 cowbirds seldom go. Friedmann (1929) does not list the bird, but 

 records the race chryseola as "a not uncommon victim of the Dwarf 

 Cowbird in southern California." 



Fall. — Of the bird in Cambridge, Mass., in the fall, William Brew- 

 ster (1906) says: "During their return migrations, which begin late 

 in August, Wilson's Blackcaps are decidedly less numerous — or at 

 least conspicuous — than in spring, and also more given to haunting 

 dry places. Indeed I have seen them oftenest at this season among 

 oaks or pines growing on high ground. Most of them pass southward 

 before the middle of September, but Mr. Ralph Hoffmann has re- 

 ported finding a young bird in Belmont as late as November 20 

 (1898)." 



