x. INTEODUCTION 



Coot, and the Phalarope, habitually swim with the same 

 ease as a Duck or a Gull. 



Geograpk- Most aquatic birds are migratory, and some take im- 

 ical dis- .. .^, /' T ,. 



tribution. niense aerial journeys in spring and autumn to and from 



their breeding-haunts. Being widely distributed over the 

 face of the Globe, their geographical distribution is an 

 important and interesting study. For information on this 

 part of the subject, and regarding allied species and repre- 

 sentative forms, frequent references have been made to 

 Mr. Howard Saunders's Manual, and to several volumes of 

 the Catalogue of the Birds in the British Museum. 



Plumage. The seasonal plumage-changes, so marked in many 

 aquatic birds, may well attract the attention of the student 

 of ornithology. Some birds, such as Gulls, several of the 

 Ducks, the Gannet and others, do not attain their mature 

 dress until the third, fourth, fifth, or even sixth year, and the 

 transition stages are often somewhat difficult to determine. 

 It is hoped that the descriptions given in the text, though 

 of a general character, will enable the reader to assign to 

 its species a bird whether immature or adult, male or 

 female, in winter or in nuptial garb. 



It is well to understand that the term winter-plumage 

 is used only in a general sense to signify other than the 

 nuptial plumage, and in all cases does not indicate the dress 

 assumed in our winter months. Many Petrels, for instance, 

 which breed in the Southern Hemisphere are in winter- 

 plumage in our summer months, though, as a matter of fact, 

 in this particular group, it would appear that the plumage 

 in the two seasons is, as a rule, identical. It may also be 

 added that, while the winter and nuptial plumages are 

 always described under separate headings in the text, there 

 are some birds which undergo only one moult in the year, 

 and so the expression similar to the nuptial plumage,' 

 does not necessarily imply a comparison, but rather that 

 the winter and nuptial plumages are one and the same 

 dress. 



The feathers of the different regions of the body have 

 been for the most part described in ordinary rather than in 

 technical terms, though such words as scapulars, secondaries, 

 primaries, and axillaries, could not well be dispensed with. 

 The positions of these groups of feathers are seen in Plate II. 



