Vol. XXII 

 1905 



Dwight, Plumage Wear and Subspecies. "2 £ 



to-day upon no better foundation than a handful of worn speci- 

 mens. The question to which I wish to direct special attention is 

 whether in describing geographical races sufficient distinction has 

 been made between the effect of climate on the feather and of 

 climate on the species. In one case the feather alone yields to 

 environment, in the other the species yields, and there is a wide 

 difference between the two. The pallid races of arid regions, 

 where dry atmosphere and sunny skies are most potent bleaching 

 agents, will illustrate my meaning. If the feather at the time of 

 its growth reflects climatic conditions by its paleness, we have here 

 an inherent character that may very properly be made the basis 

 of a subspecies, but if on the other hand the feather differs in no 

 wise from one growing in a land of moisture and fades only as the 

 months roll by, its fading is an accidental character that ought 

 never to be recognized by a subspecific name. There are those 

 who fail to grasp this distinction and believe in naming differences 

 whenever found ; but the real question at stake in not whether the 

 paleness is of sufficient degree to merit a name, but whether the 

 color is an intrinsic character. No one would think of calling 

 a sunburnt man a subspecies, but the sunburnt plumage of the 

 breeding bird is a fair mark for subspecific description ! 



The importance of the matter at once becomes obvious when 

 we consider how many races depend for their recognition upon 

 shades of color in breeding birds, and how little is known of the 

 perfectly fresh plumage of these same birds. The effect of wear 

 has been taken into account very little in naming them or perhaps 

 largely guessed at, and what is most needed to-day is definite 

 information regarding all the plumages of subspecies. This is no 

 insignificant task, and though a thankless one it will be well worth 

 the doing. My present intention is merely to call attention to it, 

 for until moulting birds, which alone show the perfectly fresh 

 plumage, are more abundant in collections than they are to-day, 

 very little progress can be made in this direction. 



A number of reputable subspecies might be selected to illustrate 

 how little the matter of wear has been taken into account in 

 naming them, but a few will suffice to show that I am not dealing 

 wholly with generalities. As a familiar example of a pallid desert 

 race, I have chosen the Desert Sparrow Hawk (Faho sparverius 



