PLAN OF THE WORK 



xvu 



Descriptions of Plumage. The descriptions, with quoted exceptions, 

 are from specimens in the American Museum of Natural History, and 

 my thanks are due the authorities of that instutition for permission 

 to use its valuable collections. I have tried to make them as concise 

 and simple and, at the same time, as detailed, as seemed necessary for 

 the purpose of identification. 



It has not always been possible to describe in detail all the plumages 

 assumed by a species at various ages and seasons, but at least the more 

 important plumage changes, and the differences due to sex, age, and 

 season are indicated. It should be explained that, where the sexes 

 are alike, they are described under the subheading "Ads.," meaning 

 adult specimens in breeding dress. The subheading "Im." in the light 



FIG. 2. Spotted (a), streaked (6), barred (c) and margined (d) feathers. 



of our present more exact knowledge, is somewhat indefinite; but, as 

 has just been said, absolute exactness in this connection is not possible 

 in a book of this size, where descriptions are intended primarily for the 

 purpose of identification. It may be said, however, that, with but few 

 exceptions, "Im." signifies a bird in first winter plumage, or the one 

 following that (the Juvenal) in which the bird leaves the nest. Where, 

 however, the Juvenal plumage is worn for some time, as with the Snipe, 

 in which it largely takes the place of a first winter plumage, then it is 

 described under the term "Juv." 



Measurements. All the measurements given are in English inches 

 and hundredths. Those of birds are average measurements, taken for 

 the most part from specimens in the American Museum of Natural 

 History. I have also, with the author's permission, made use of the excel- 

 lent series of measurements in Dr. E. A. Mearn's Birds of the Hudson 

 Highlands. A variation of about ten per cent from the figures given may 

 be expected. 



The total length (= L.) of a bird is found by gently stretching the 

 specimen, laying it on its back, and measuring the distance from the 



