OF THE UNITED STATES 191 



in the two sexes to be practically alike, but in the female the 

 middle-tail feathers are not so long as they are in the male. 



The parts below, as well as the neck, are white, the latter being 

 shaded with light yellow. The head behind is sub-crested, the 

 feathers being of a brownish-black color, which is also extended 

 to include the area anterior to the cheeks and the top of the head. 

 Above, this species is of a deep slate color, with the exception of 

 the primaries and secondaries of the wings, the lateral tail-feath- 

 ers and the posterior halves of the central pair, all these parts 

 being of a blackish-brown, more or less lustrous in tint. It is not 

 uncommon, I learn, to meet with melanotic phases of plumage in 

 the jaegers, to an extent to be considered almost a normal spe- 

 cial condition. As a rule, these birds inhabit the sea coasts and 

 great lakes of the arctic and sub-arctic regions, but there are ex- 

 ceptions to this, and the Long-tailed jaeger in winter occurs as 

 far south as the Gulf of Mexico. With us, however, they all pass 

 to the far northward to breed. Their habits of nidification are 

 more or less like the gulls, and they lay from two to three dark- 

 colored eggs, variously spotted. 



In the matter of flight, the jaegers are pre-eminently powerful 

 and rapid, and as they are the most relentless avian pirates that 

 infest the high seas, they put their varied aerial accomplishments 

 to no less base a purpose than persistently harassing all the 

 smaller species of gulls and the terns, forcing them to either dis- 

 gorge their food or robbing them of such as they may have in 

 their beaks at the time of their making their attacks. 



A great deal more might be said here about these voracious 

 longipennine robbers, but we will pass now to a consideration of 

 the remaining subfamily of the group of the terns. Of these we 

 have many species, for which some four genera have been cre- 

 ated, as mentioned above. 



Unless others have been discovered within the past very few 

 years, I am familiar with but three species of the birds we call 

 skimmers, of the genus Ryncliops. Two of them are found in 

 Asia, and there is our own species, known as the Black skimmer 

 or Razor-bill, which on the Atlantic coast ranges as far north as 

 New Jersey, but has been occasionally taken in as high latitude 

 as that of the Bay of Fundy. 



Audubon has an excellent colored drawing of the Black skim- 

 mer (R. niger), in his work, and this I have copied to illustrate 

 this bird (Fig. 52). 



