88 THE MOLT. 
related species molt differently, but the manner and time 
of molting among individuals of the same species may 
vary according to their sex, age, and physical condition. 
At the close of the nesting season all birds renew 
their entire plumage by molting. The following spring, 
before the nesting season, most birds molt their body 
feathers, retaining those of the wing and tail. <A few, 
however, like the Bobolink, have a complete molt at 
this season also. Others molt only a few of the body 
feathers, while some birds are adorned at this season 
with special nuptial plumes. 
The beautiful aigrette plumes of the Heron consti- 
tute a nuptial dress ot this kind. It is for these plumes 
that the birds have been slaughtered in such enormous | 
numbers that if the demand continues they will speedily 
become extinct. 
Some birds, whose fall plumage is edged with a dif- 
ferently colored tip to each feather, do not molt in the 
spring, but acquire their wedding dress by the slow wear- 
ing off of the fringes to the feathers which have dis- 
ij 
. fiy\\| I WW Diy 
October. January. March. June. 
Fi. 23,—Feathers from back of Snowflake, showing seasonal changes in form 
and color due to wearing off of tips. (Natural size.) 
guised them during the winter. The Snowflake, for 
instance, changes from brown and brownish white to 
pure black and white by losing the brown tips which 
have concealed the black or white bases of his feathers, 
