238 PatMER, The Maryland Yellow-throat. jue 
the length and character of the migration can influence the growth 
of these feathers, greater wing power having developed and found 
expression in longer outer primaries as the length of the migra- 
tion journey gradually increased in the individuals subject to the 
change. The three outer tail-feathers of this specimen on one 
side, four on the other, are still in place, but the central ones 
have dropped out and new ones are growing. A female, No. 3503, 
August 10, 1894, is in somewhat similar condition, the outer 
primaries are further advanced and the outer new tail-feathers 
are of differing lengths. The body change is nearly complete. 
Other specimens show similar changes, commencing about the 
middle of July and completed by the middle of August. This 
molting takes place all along the Atlantic watershed about the 
same time, but the birds of any given locality move further south 
before it is completed. It would seem that the night flights 
begin when the wing molt is fully completed. 
A spring molt undoubtedly occurs, especially in the males, but 
it is confined to the face and throat. The yellow of the throat 
and most if not all of the immature facial black and the white 
eyering is replaced, so that the immature spring bird is hardly 
distinguishable from an adult. No spring molt appears evident 
on female specimens. Occasionally a male specimen is taken in 
spring which has not had a spring molt. I have taken several 
about Washington and have seen others. Immature birds of all 
the forms have slightly shorter wings and primaries during their 
second summer. 
The high and arid character of the habitat of occidentalis 
accounts for the paleness of spring, summer, and most winter 
specimens, but the darkness of freshly molted birds tells a dif- 
ferent tale. As already stated, the immature when freshly 
molted are as dark as eastern birds and the adults are scarcely 
less so. Buta paling of the plumage rapidly takes place, being 
entirely caused by the bleaching action of the dry, clear, western 
atmosphere. The white feathers bordering the facial black are 
at first ashy, but little paler than in eastern birds, but they soon 
bleach even before they have fully grown, except where, as in 
immature birds, they are protected by brownish tips. This 
darker coloration of freshly molted birds is an index of the char- 
