Vol. XVIII 

 1901 



I DwiGHT, Moults and Plumages of Gulls a7id Terns. C o 



seldom uttered as they circled among the clouds of Terns in the 

 proportion of perhaps one to one thousand. The Kittiwakes 

 were obtained from a small flock, and it is of interest that this 

 species does not breed within several hundred miles of Sable 

 Island. Birds of several other species in a similar first nuptial 

 plumage have occasionally been taken, but their significance has 

 not been understood. We may attribute the lateness of their 

 prenuptial moult to lack of vigor, if we please, and it is possible 

 some of the midsummer birds that we have supposed were adults 

 passing by an early postnuptial moult to winter plumage are really 

 immature birds, but for further light on this point we must look 

 to field observers. As such birds assume in early summer a win- 

 ter dress, it is possible that their moult is really a first postnuptial, 

 no further feather change occurring for a year, but it seems more 

 probable that a postnuptial moult takes place later when they 

 assume for the third time in succession a plumage that is certainly 

 of the winter type. The Kittiwakes cited, and some museum 

 specimens of several other species, seem to point to a similar 

 sequence among Gulls. 



Much might be said upon the subject of wear, under which I 

 include all the destructive results of abrasion and bleaching, but 

 suffice it here to direct attention to a couple of points. One is 

 the extremely marked fading of the buff edgings of plumages of 

 young birds, especially the juvenal, in which the buff often becomes 

 white ; and the other is loss of the ' frosting ' or ' silvering ' on the 

 wings of many species, which produces black primaries. The 

 ^frosting' is due to elongated, curved and frilled barbules on the 

 distal sides of the barbs, and when the barbules are worn off their 

 black basal portion becomes conspicuous. As a rule the fourth 

 primary of each wing appears to suffer most, the third, second 

 and first or distal blackening later in the order indicated. 



We may now take up in their natural sequence the plumages and 

 moults of a Tern, of a small Gull and of a large Gull, the three 

 chosen being typical of all the others, and I begin with the Tern, 

 as the number of recognizable plumages are fewer owing to the 

 complete -double or semiannual moult. 



The sexes among the Laridae are fortunately alike in all plumages, 

 only to the more salient features of which reference will be made 



