THE BAY-BREASTED WARBLER 



( Dendroica castanea. ) 



This tastefully colored and beautiful 

 little Warbler, while it has quite an ex- 

 tensive range, and migrates through the 

 eastern portion of North America as far 

 to the westward as the Great Plains, it 

 is not a well known bird. During its 

 migrations either in the spring or fall, it 

 does not tarry long, and as Dr. Chapman 

 has said it is ''generally uncommon 

 enough to be considered somewhat of a 

 prize." At times, however, it is quite 

 common but this usually only occurs in 

 the northward journey of the spring. Its 

 nesting range extends from northern 

 New England and northern Michigan, 

 northward to Labrador, and Hudson 

 Bay, and it winters through Central 

 America and in South America to Col- 

 ombia. Regarding the migrations of 

 these Warblers, Mr. Maynard has said: 

 "Avoiding the eastern and middle states, 

 the majority pass along the borders of 

 the Great Lakes, through Ohio, southern 

 Illinois, down the Mississippi Valley, 

 across into Texas, and so on into Mexi- 

 co and Central America, where they win- 

 ter." Probably the reason why they are 

 usually considered much rarer during 

 the fall migrations than during those of 

 the spring, is that the young Bay-breasts 

 bear a striking resemblance to the young 

 of the black-poll warblers which are gen- 

 erally very abundant during the fall 

 southward migrations. Even the identi- 

 fication of specimens of the young of the 

 two species is frequently very difficult, 

 and while they are alive, it is practically 

 impossible when free. Many observers 

 who have listened to the song of these 

 Bay-breasted Warblers have likened the 

 sound at the beginning to that of the 

 black-poll, and at the end to that of the 

 redstart. Mr. Langille has said, the song 



''bears to my ear no resemblance what- 

 ever to either, but is a very soft warble, 

 somewhat resembling the syllables tse- 

 chee, tse-chee, tse-chee, tse-chee, tse-chee 

 but far too liquid to admit of exact spell- 

 ing." Mr. Langille's views of the sweet 

 voices of these birds are certainly very 

 satisfactory to all who have heard them 

 singing. 



During the fall migrations, when it is 

 so difficult to distinguish between the 

 Bay-breasts and the black-polls, the ob- 

 servations of Mr. Frank W. Langdon 

 may be helpful. He says : "A compari- 

 son of specimens of both species shows 

 that the chin or feathered space be- 

 tween the forks of the lower mandible, 

 is considerably wider in castanea (Bay- 

 breasted) than in striata (black-poll) — 

 arguing a greater width of base of bill 

 in the former species. The bill of cas- 

 tanea is generally the larger in every way 

 but its greater width at the base is es- 

 pecially evident. This character appears 

 to be constant in a number of specimens 

 from this (Cincinnati) and other locali- 

 ties, and being an anatomical peculiarity, 

 it is, of course, much more reliable as a 

 diagnostic mark than any slight differ- 

 ences in coloration." 



The nests of these Warblers are com- 

 pact and somewhat cup-shaped struc- 

 tures. They are usually built in conifer- 

 ous trees at a height of from five to 

 twenty feet above the ground. The ma- 

 terials used in their construction are fine 

 strips of bark, small and wiry twigs, 

 small and fibrous roots, and they are lined 

 with the down of plants, moss, and ani- 

 mal hairs. The usual number of eggs in 

 a set is four. They are white with a 

 slight tinge of bluish, and speckled with 

 reddish brown at the larger end. 



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