( 503 ) 



RICHARDSON'S JAGER. 



Lestris Richardsonii, Swains, 



PLATE CCLXXII. Male and Young. 



This bird, though rare on the coast of the United States, visits the 

 shores of Massachusetts and Maine, where, during winter, it is seen over 

 the bays and inlets, to which various species of Gulls also resort at the 

 same season. It is more shy and difficult to be approached than the Po- 

 marine Jager. Its flight is rapid and greatly protracted ; and, like the 

 other species of this genus, it harasses the smaller Gulls and Terns, for- 

 cing them to disgorge their food. Dr Richardson informs us that it 

 breeds in considerable numbers in the barren grounds, at a distance from 

 the coast, and that it feeds on testaceous mollusca, which are plentiful in 

 the small lakes of the fur countries. I am unable to afford any informa- 

 tion respecting its habits ; nor can I state decidedly the number of eggs 

 which it lays, although I have procured several of them. They measure 

 two inches and three-eighths in length, by one inch and five-eighths in 

 breadth, are of an oval rather pointed form, and have a dull greyish-yel- 

 low ground, patched with umber and faint purple, the markings closer 

 towards the larger end. I am extremely doubtful as to the right which 

 this bird has to rank as a species distinct from L. parasiticus. 



Lestkis Richardsonii, Richardson's Jager, Swains, and Richards. Fauna-Bor. 

 Amer. part ii. p. 433 Nuttall, Manual, vol. ii. p. 319. 



Adult Male in Spring. Plate CCLXXII. Fig. 1. 



Bill about the length of the head, rather slender, straight, the tip 

 curved. Upper mandible with the dorsal line straight, toward the end 

 curved, the ridge broad and convex, the sides separated from the ridge 

 by a narrow groove, extremely narrow and convex, the edges sharp and 

 inflected, the tip compressed, rather obtuse. Nostrils in the fore part of 

 the nasal groove, nearer the tip than the base, submarginal, pervious, 

 linear-oblong, wider anteriorly. Lower mandible with the angle long and 

 narrow, a slight prominence at its extremity, beyond which the dorsal 

 line is straight and ascending, the sides sloping outwards and convex, the 

 edges sharp and inflected, the tip obliquely truncate and rather obtuse. 



