20 GENERAL HISTORY OF BIRDS. 



In most species of birds, it would simply be inviting disaster from their 

 enemies lif the wing feathers were shed at once, as in certain ducks and ( 

 geese, consequently we find that the molting change in the large feathers be- 

 gins with the inner primaries and the adjoining secondaries. Usually alter- 

 nate feathers are renewed and almost fully grown before adjoining feathers 

 are dropped and usually also the secondaries are entirely renewed before the 

 primaries, the decoi'ative tertials as in all decorative feathers changing last. 

 In this way no gaps occur, or at least gaps are reduced to a minimum. When 

 these flight feathers are serviceable, the smaller wing feathers are changed and 

 also the outer primaries. It often occurs on specimens that the flight feathers 

 of the wing are new except the three or four outer primaries which are still 

 of the old growth. To this fact is due another, which is an interesting phase 

 of feather growth correlated with the economy of species, for in species of 

 good power of flight requiring great wing power to escape enemies, as in most 

 of the waders and in migrants performing long journeys, especially over seas, 

 we find that the outer primaries are long; while in sedentary species, especial- 

 ly of woodland types, and tropical species, the wing is rounded and the outer 

 primaries are short. Thus the character of the outer primary growth es- 

 pecially is determined by the strain on the wing, the character of the flight. 



It often happens that from some cause the molt is retarded or even en- 

 tirely stopped so that we find feathers of the old winter dress mixed with new 

 ones of the breeding plumage. Rarely also a few feathers of an earlier 

 change are also retained. The molt is nearly always more complete on the 

 older males because of the greater sexual feather values. 



COLOR CHANGE WITHOUT MOLT. 



Until within a few years past it was not the custom of ornithologists to 

 preserve molting specimens of birds or to take any active interest in the sub- 

 ject of molt. In the absence of series of specimens illustrating the sequence 

 of molting changes, and especially with many so-called intermediate specimens 

 showing evidently a possible series of changes with no traces of molt, it be- 

 came the custom of many to accept unreservedly for some or all species, the 

 belief that a full grown and therefore dead feather could at a certain time re- 

 juvenate itself and acquire a fresh growth and color, even acquiring a stronger 

 and much richer coloration than the full color of its species. 



As, however, the matter has been more fully studied and larger and more 

 varied collections obtained, it has been gradually shown that in all the cases 

 brought forward to show so-called color changes of feathers, molting had ac- 

 tually occurred and was the responsible agent. Age and sex are important 

 in determining the extent and strength of molting change on a bird, and when 



