ORNITHOLOGIST 
—AND— 
_OOLOGIST. 
$1.50 per 

FRANK B. WEBSTER, PUBLISHER. Single Copy 
Annum, Established, March, 1875. ; 15 Cents. 
VOL. XI. BOSTON, MASS., APRIL, 1886. No. 4. 
Aptoso-Chromatism. 
BY WALTER HOXIE, FROGMORE, 8. C. 

The above name was suggested to me about a 
year ago, by Dr. Coues, to denote the ‘‘moultless 
color change” in the feathers of birds. I learn 
from him that it is an almost untried field of re- 
search in ornithology, and it is therefore with a 
great deal of diffidence that I now open the sub- 
ject, hoping that the attention of others may be 
directed to this exceedingly difficult subject of 
study. 
The physique of birds is eminently elastic. 
The feathers are a sensitive and highly organized 
glass of tissues. What wonder then that they 
respond promptly to the annual changes which 
pervade all other parts of the birds’ economy. 
That these changes are great none will deny. 
Compare the weight of a bird with the weight of 
its egg and consider for a moment what an enor- 
mous amount of animal substance has been in a 
few short weeks—almost I may say, days—de- 
veloped. What wonder, then, that there is a re- 
action and that the feathers partake in it as well 
as the rest of the system. Why the color effects 
should be so much more marked in the male, than 
in the female, is no more occult a phenomenon 
than the superior brilliancy of the male plumage 
at all times. Neither is it a refutation of the 
theory that a change has occurred in the feathers 
because a marked difference in their color is not, 
“apparent. The male and female of many birds! 
are identical in plumage at all seasons. But! 
whereas the female has to make a large secretion 
of animal substance from her system to perfect 
the eggs, the male at the same season only de- 
velops a smaller amount of a highly specialized 
substance ; his system is higher strung, so to 
speak, and the attendant phenomena more ap- 
parent. 
How large a factor the food supply may be in 
the aptoso-chromatic phenomena I am still un- 
able to estimate. That it is a factor at all, I am 
sometimes inclined to doubt. My notes upon 

birds food are not as yet sufficiently voluminous 
to determine this with certainty. In the merry 
days of Falconry the food was considered to have 
a marked effect upon the growth as well as the 
color of the plumage of young hawks. Dealers 
in cage birds often hint of secrets in feeding, for 
For 
the present, at least, I consider it safe to eliminate 
the question of food altogether from a discussion 
of aptoso-chromatism and mainly to consider the 
changes consequent upon the preparation for a 
completion of the nuptial task. 
the development of color as well as song 
During the past spring it was my good fortune 
to be able to examine a large series of specimens 
of the Bobolink; males in perfect feather but as 
yet not in full nuptial dress, showed little if any 
indications of swollen testes. On the other hand 
all males in full plumage, as it is called, had the 
testes swollen and turgid, although in fully half 
the specimens examined the moult was not com- 
pleted; that is, they were not in as perfect feather 
as their less precocious comrades. This goes to 
show .the independence of aptoso-chromatism 
from the regular phenomenon of moulting. In 
the fall no full plumaged males are ever seen in 
this region, and all of both sexes are in complete 
feather. 
The rest of my recent notes on this subject re- 
fer mainly to the Summer Red-bird, the Cardinal 
and the Nonpareil. Among these three species 
the males seem to greatly outnumber the females, 
and only three mated males show full nuptial 
This fact I have often noted. The parti- 
duller Cardinals, who 
dress. 
colored Red-birds, the 
show much ashy edging to their feathers and 
the green male Nonpareil, all prove to be un- 
mated. A parti-colored Red-bird was adopted 
by a female, whose full-plumaged mate had been 
shot, and in twenty-two days he himself was in 
full dress. The females of all three of these 
species show a decided change on the under 
parts immediately before toying. The Red-bird 
assumes almost an orange tinge, the Nonpareil 
a strong pinkish flush, and in the case of the 

Copyright, 1886, by Eaton Crier and F. B. WEBSTER. 
