38 THE STORY OF THE BIRDS. 
here and there. Precocial birds, which leave the nest 
at once, shoot out their wing quills before grown, in 
keeping with the demands of safety in their exposed 
conditions, and they get a new and better set later. 
Altricial birds wait till they are nearly grown to ac- 
quire their wing quills (fit for flight), and do not 
usually renew them that season. In some species 
some ornamental plumes also are shed in a few 
weeks after they are acquired, long before the nor- 
mal fall molt, while other plumes are worn the year 
around. 
The fall molt seems necessary on account of the 
wear and fading of the plumage, brought about by the 
business of the year, and, as Darwin suggests, in keep- 
ing with the demands of warmth for the coming win- 
ter. Incidentally with it often go the heavy plumes 
acquired in the nesting season, but, as noted, not al- 
ways. Since we are sure that many of these orna- 
ments are of comparatively recent origin, the getting 
rid of these could not be the purpose of the autumnal 
change. 
While we may feel that the purpose of the spring 
molt is ornament, and that the object of intermediate 
molts is protective coloring, yet we are hopelessly in 
the dark about how these changes of suit were origi- 
nally brought about or why a change should so fre- 
quently result so suddenly in a new color. 
The molts may have originated, of course, in the 
necessity for repair, as noted; for it is well known 
that there can be as many renewals of the feather as 
there are losses, so that (within the limits of the bird’s 
