BAY-BREASTED WARBLER. 255 
striata, that is sometimes impossible to distinguish them with certainty. Castanea is, 
however, tinged with buffy or ochrey below, instead of the clear pale yellowish of 
striata, moreover, castanea is usually not streaked on the sides at all. Size of striata. 
Habitat, Eastern United States; north to Hudsen Bay; south to Guatemala and 
Darien; west to the Plains. 
Irregular migrant in spring, abundant and regularin the fall. I have 
found this warbler the most decidedly irregular of all our spring migrants 
which can be considered at any time common, having taken it but one 
season, Spring of 1874, when, as stated, it accompanied the Black poll 
Warblers in great numbers, and frequented beech and mixed woodiand. 
It appears to be less active than most of the genus. Dr. Kirtland mea- 
tions having secured numbers of them, and does not mention any irregu- 
larity. Mr. Read gives it as abundant, and states that he has “seen it as 
late as the last of June.” 
In the fail they are to be found in September and October, in great 
numbers, remaining, with the Black-poll Warblers, later than any of the 
genus, excepting the Yellow-rump. Svwme fall specimens have the brown 
of the sides redder than in spring, though not so extensive; but by far 
the greater number of our fall birds cannot be distinguished at any dis- 
tance, from D. striata, and a considerable proportion are difficult to dis- 
tinguish from the young of striata. In addition to the diagnostic marks 
given in the above description, it may be stated that the greenish of the 
breast of-young striata often shows obsolete streaks, while no streaks 
whatever are to been on the brownish or buffy-whitish of castanea, except 
perhaps, dusky centres on the under tail coverts. Mr. Langdon, in his 
Revised List, gives the following important structural marks of distine- 
tion. “ A comparison of specimens of both species shows that the chin, or 
feathered space betweea the forks of the lower mandible, is considerably 
wider in castanea than in striata arguing a greater width of base of bill 
in the former species. The bill of castanea is generally the larger in 
every way, but its greater width at base is especially evident.” 
This warbler has been found breeding only in the most northern Uni- 
ted States and northward. The nest is placed in a tree, and is said to be 
large for the size of the bird, and to resemble the nest of the Purple 
Finch. It is described as composed of fine twigs and moss, lined 
with rootlets, mossand hair. ‘“ Tie eggs varied in length from .71 to .65 
of an inca, and in breadth from .53 to 50. Their ground color was a blu- 
ish green, thickly spotted with brown, and generally with a ring of 
confluent blotches of brown and lilac around the iarger end.” 
