440 APPENDIX. 
Sylvicolide or warblers (§ 9). Young students will find the 
young of this family very confusing, from their frequent simi- 
larity one to another, and their abundance during the fall-mi- 
grations. It is best to study warblers in the spring, and to 
avoid immature birds until the differences between their parents 
are mastered. The young of those species, not further men- 
tioned, either resemble the females or the males also, or are 
characterized by indistinct markings and impure colors, such 
as greenish-blue, yellowish-white, ete... Helminthophaga celata 
is *‘ often difficult to distinguish in immature plumage; but a 
general oliveness and yellowness, compared with the ashy of 
some parts of ruficapilla, and the different color of the crown- 
patch in the two species, will usually be diagnostic.” (Coues.) 
The young male of the ‘ Black-throated Blue” (Dendreca 
cerulescens) resembles the adult male, but the colors are im- 
pure, and the black restricted. The immature ‘‘ Yellow-rumps” 
(D. coronata) are common during both migrations. Their col- 
oration varies from an imperfect full dress to the following ex- 
treme. Beneath, white or whitish, with slender streaks ; above, 
chiefly brown, with more or less yellow, especially on the rump 
(which is concealed by the wings when closed). The other 
young Dendreece with yellow rumps are maculosa (Black and 
Yellow Warbler) and tigrina®? (Cape May Warbler). The 
former have more or less distinct (and pure ?) yelfow beneath, 
*¢ small tail-spots near the middle of all the feathers except the 
central ;” and are rather gray above. The latter are greenish 
above. ‘The young Yellow ‘* Red-poll” (D. palmarum), with a 
yellowish rump, has the ‘ tailspots at very end of inner webs of 
two outer pairs of tail feathers only, and cut squarely off—a pecu- 
liarity distinguishing the species in any plumage.” (Coues.) 
Of the Bay-breasted Warbler (D. castanea) the young ‘so 
closely resemble young striata [‘* Black-poll”], that it is some- 
times impossible to distinguish them with certainty. The upper 
parts, in fact, are of precisely the same greenish-olive, with 
black streaks ; but there is generally a difference below — casta- 
nea being there tinged with buffy or ochrey, instead of the 
clearer pale yellowish of striata; this shade is particularly ob- 
servable on the belly, flanks and under tail coverts, just where 
striata is whitest ; and moreover, castanea is usually not streaked 
on the sides at all.” (Coues.) The young Blackburnian War- 
bler is not unlike these, though sufficiently like the female to 
be distinguishable. The other species require no notice, unless 
3 Properly Perissoglossa tigrina. 
