(334 BIRDS FROM YEZO, JAPAN—-STEJNEGER. 
‘Zanthopygia narcissina (TreMM.). (209) 
Twenty-seven specimens, the particulars of which will be found below. 
This series is the most interesting and most convincing one I have 
ever seen demonstrating the curious and still but little understood 
change of color in the old plumage without abrasion of the feathers or 
shedding of their margins, as it takes place in some birds in spring. 
At the meeting of the German ornithologists in Altenburg, July, 1852, 
Mr. Leopold Martin demonstrated the fact that the young black and 
white Flycatchers of Kurope exchange their juvenile gray plumage for 
the adult black one without a molt, and without shedding the margins” 
of the feathers (printed in Journ. f Orn., 1853, pp. 16-19). Curiously 
enough, Dr. Hermann Schlegel on the same occasion laid a similar dis- 
covery betore the same society (printed in Naumannia, IL, ii, 1852, pp. 
19-40), but unfortunately both gentlemen overestimated the frequency 
of the phenomenon. Schlegel tried to prove that such a change of 
color without a molt or marginal shedding takes place in all birds, 
while the feathers are only molted once a year, viz, in spring; and Mr, 
Martin, without committing himself positively, expressed a somewhat 
similar opinion. An animated discussion sprang up in the journals 
mentioned, in which especially Gloger, Brehm, and Giitke participated, 
and it was finally conceded on almost all sides that such a change of 
color takes place in certain birds, but that so far from it being the usual 
process, the change of color independent of molt or marginal shedding 
must be regarded as the exception. Schlegel’s unwarranted general- 
ization, however, had brought the whole theory into disrepute; the 
subject was soon dropped, and but few later ornithologists have paid 
any attention to it, in spite of the fact that it is one of the most in- 
teresting questions in ornithology. The great difficulty is in giving 
a satisfactory physiologic explanation of the process, which to-day is 
nearly as much of a mystery as it was thirty years ago. People were 
willing enough to admit the possibility of a change of the color, but it 
was found that this was accompanied by an apparent renewed growth 
of the feathers, a process by which the worn and broken plumes seemed 
to undergo a complete mending or renewal. This phase of the ques- 
tion is admirably illustrated in Henson’s series, and I must confess that 
T am not prepared to accept any of the theories which have been 
proposed. But although unable to offer a satisfactory explanation of 
the phenomenon, it will not do to deny the facts, and we must leave 
the solution of the question to some painstaking physiologist, who shall 
take up the subject in a careful and empirical manner. 
Of Henson’s birds eight are males in full plumage, and two adult 
females; six are young birds after the first autumnal molt, and eleven 
are spring males in all possible gradations between the young and the 
adult plumage; one similar bird is in the U.S. National Museum, and 
one in Petersen’s collection from Nagasaki, 
t 
