16 
Brewster’s Descriptions of the First Plumage 
sion that has previously resulted either from misapprehension, or 
from a too free use of certain distinctive terms. 
While it is to be regretted that the specimens at hand do not 
furnish full series of even all the commoner species, it is nevertheless 
hoped that, by calling attention to this hitherto neglected field, an 
impetus will be given to future investigation that may result in a 
more complete knowledge of the subject than can here be presented. 
Before proceeding to a detailed consideration of specimens it may 
prove of interest to state briefly a few generalizations regarding the 
comparative development of the young in different families of 
birds. 
Among North American Altrices the young of most species are 
born with thin patches of delicate, soft down, restricted mainly to 
the feather-tracts. Beneath this fluffy down the feathers are 
already forming; these soon appear, bearing at their summits the 
little tufts of down that formed the down-patches. Meanwhile the 
remiges and rectrices have started, and, growing with marvellous 
rapidity, the bird is soon able to take wing. The contour-feathers 
have now also nearly reached their full growth, and differ in both 
structure and color from the later stages of plumage, these feathers 
being softer and of a more open texture than those that succeed 
them. This is the stage of plumage technically characterized 
throughout the following paper as the first plumage. Though eva- 
nescent, it is usually worn for several weeks after the bird has left the 
nest. It is then moulted , and the regular autumnal plumage suc- 
ceeds. 
The remiges and rectrices are, however, nearly always retained 
until the next regular moult , exceptions to this rule being afforded 
by the families Tetraonidee and Picidoe and the genus Philohela , 
and probably by a few other groups, in which the remiges and rec- 
trices are moulted w T ith the rest of the first plumage. 
The early tegumentary development of most Prcecoces (birds 
whose young run about at birth) is quite different : they are 
densely clothed with dowm until of large size, when, coincident with 
the sprouting and growth of the remiges and rectrices, the feathers 
of the full autumnal plumage appear. In short, the first plumage 
of Altricial birds seems to be omitted or perhaps replaced in the 
Prcecoces by their more complete and longer worn, downy plumage. 
A few conspicuous exceptions occur among both groups. Thus, 
many Raptor es differ from the Altrices in being densely clothed with 
