146 CHADBOURNE, Spring Plumage of the Bobolink. Awa 
In conclusion, I wish to add a few words on the subject of 
‘MOULTING’ in its wider application y— First, it is most important 
to have an exact definition of the word ‘ mouw/t,’ which has often 
been used with very different meaning ; namely, for new feather- 
growth, of the whole, or of a part of the plumage, for feather-loss, 
for complete, or slight changes of color whether caused by feather- 
change, by true color-change, or simply from mechanical ‘ wear 
and tear,’ and the shedding of the deciduous tips. The word 
‘moult’ is too firmly established, and too convenient to be aban- 
doned, but its use should be restricted to “e regular seasonal 
Jeather-change, WITHOUT REGARD TO THE COLOR OR COLORATION 
OF THE PARTS CONCERNED; and when not farther qualified, the 
shedding of all the feathers, including the large flight feathers, should 
be understood. ‘The expressions, ‘feuther-loss,’ ‘new feather-growth’ 
and ‘ feather-change, are scientifically exact, they define them- 
selves, and are the equivalents of German terms, already in use. 
Why should not these, or some similar words be adopted by us. 
Second : — The meaning of ‘cCOLOR-CHANGE’ would seem to be 
sufficiently clear, yet it has been very differently interpreted by 
writers on the colors of feathers; and such sentences as, “color- 
change, aside from the effects of exposure and fading ”’, are often 
used. Moreover, as a rule, those who are sceptical on the 
subject of ‘color-change without moult,’ refuse to admit that an 
alteration from a darker shade to a lighter tint is an instance of a 
change in color. Yet obviously, the development of a lighter 
color may be either a ¢rue color-change, in the most strict 
sense, or it may be purely mechanical with resulting loss of 
substance. As applied to feathers therefore, any perceptible 
departure from the former shades and tints, or from their previous 
distribution, is a color-change. When used in connection with the 
subject of ‘color-change without moult,’ however, it is clearly 
intended to exclude alterations due to causes, acting from out- 
side the body, and mechanically; and thus limited, a TRUE 
COLOR-CHANGE 7s wholly, or in part due to conditions within the 
organism, or within the feather itself ; to alterations in the coloring- 
matter, or in its distribution in the feather. 
Third : — FapDInG, as already stated, implies a gradually progres- 
sive change from a darker shade to a lighter tint, resulting from 
conditions external to the body. 
