134 
PROCEEDINGS OE THE ACADEMY OP 
parts, — the transverse bands being broadest on the flanks and under tail and 
wing coverts, narrowest in the middle of the belly. The primaries are 
brownish black, narrowly tipped with rufous, their shafts yellowish, their 
inner webs fading basally into white. The tail has the same coloration as 
the wings. The central feathers project about three-fourths of an inch. 
As the bird above described grows older, the bill and feet become stouter, 
the cere better developed ; while the rufous everywhere gives way to the 
darker color. No special stage can be characterized, however, until the 
rufous is far outweighed by the dusky. Then we have — 
(No. 18652). — Size and general proportions nearly those of the adult. Bill 
and cere perfectly formed ; feet mostly black, but with some yellow blotches. 
The upper parts are unadulterated with any rufous bars ; the deep brownish- 
black pileum has appeared, and the sides of the neck have obtained their 
yellow nuance, which contrasts conspicuously with the fuliginous background. 
Evidences of immaturity, however, are found on the under parts, where the 
dark color is mixed with illy-defined transverse bars of ochraceous. Rufous 
is also found at the bend of the wing, and on the under wing and tail coverts. 
The primaries are still whitish baso-externally, as are also the rectrices. The 
central rectrices project 2J inches, and have the tapering form of those of the 
adults. 
By the disappearance of the little rufous mentioned above, we have arrived 
at a very marked and decided stage, — viz : 
(No. 20362).— With the size and proportions of the adult. Wholly deep 
dusky ; darker and more plumbeous superiorly ; lighter, and with a fuliginous 
tinge interiorly ; the pileum quite black ; the latero-nuchal yellow, well 
pronounced ; the remiges and rectrices quite black ; feet black. 
Having reached this perfect dusky stage, we will go back again to the 
young plumage first characterized, and show how specimens occasionally 
seem to proceed at once towards the adult condition with the white under 
parts. For example — 
(No. 2754). — The juvenility of the specimen is attested by its small size, 
delicate bill and feet, little projection of the central rectrices, general molli- 
pilose condition of plumage, &c. The rufous of the very young bird, instead 
of giving way everywhere to dusky, yields to this color only on the upper 
parts and crown ; on the sides of the head, neck, and the whole under parts, 
whitish being the predominating color, — the continuity of this last being 
interrupted by indistinctly marked dusky bars. The yellow of the sides of 
the neck has not yet appeared. There is the same white space on the bases 
of the wings and tail as exists on the very young. The central tail feathers 
only project about 1J inches. 
By an attentive consideration of the preceding facts, it will be evident that 
we have found the same very young plumage to change gradually through 
one series of specimens into the fusco-unicolor state ; through another series 
into a stage which tends to pass directly into the normal plumage of the fully 
adult bird, without going through this dusky epoch. What can we deduce 
from this perplexing fact? Does one sex assume this dusky plumage at a 
certain age, and the other not ? Does this dusky state constitute the normal 
adult plumage of one sex? Is it a seasonal feature, which both sexes return 
to at certain periods in each year? — or, finally, does it constitute a purely 
accidental, but constant variety ? Authors of weight are divided on each of 
these points. 
I reject entirely the last hypothesis, — viz : that some birds attain to this 
dusky stage and retain it during their lives, though they may have sprung 
from normally colored parents, and have normally colored progeny. What- 
ever age or season, or whichever sex this state of plumage indicates, I think 
there can be no reasonable doubt that it is a normal and constant stage which 
every individual of one (or both ?) sexes passes through or attains to, in its 
[May, 
