Feathers 45 
part of the young birds to take care of themselves as 
soon as hatched. They pass the entire first moult within 
the egg itself, and are covered with perfect feathers and 
fully developed flight-quills when they emerge from the 
shell. A wild duckling, although provided with a thick 
waterproof coat of down, has, like the robin, to wait a 
long time for his flight-feathers; but his aquatic habits 
and powers of diving make the dangers to which he is 
exposed far less than is the case with the young Bob- 
white. 
The causes of wear and disablement to feathers would 
make a long list if we but knew them all. As one instance 
take the wings of a Chimney Swift after she has reared 
her brood in the depths of some blackened chimney, or 
even a lightning-struck hollow tree. Her primaries are 
so matted and clogged with balls of soot that she would 
often find the migratory flight dificult indeed, were the 
feathers not replaced by new ones. 
When birds return from the South, and when a hint 
of spring warns winter residents to cease their roving, 
they prepare to develop all the advantages which may 
in any way aid them in securing a mate. Some indus- 
triously practise dance-steps, others flight-evolutions, a 
larger number rehearse their songs under their breath, 
while still others passively await the development. of 
plumes, gorgets, spots and splashes of colour which, if 
the feathers come out large and brilliant, may stand them 
in as good stead in their wooing as any song or antic. 
Thus we find a class of birds which have a partial or com- 
plete moult in the spring. These feathers may last all 
