16 BIRDS OF PENNSYLVANIA. 



this species are used in many sections along the Atlantic coast, especi- 

 ally in some of the southern states, for table purposes. 

 Larus Philadelphia (ORD.). 



Bonaparte's Gull; " Little Gull." 



DESCRIPTION (Plate 52). 



Adult. Bill, black ; tarsi (dried skin), reddish-yellow ; head and upper part of 

 neck dark lead color ; lower part of neck, under parts, rump and tail pure white ; 

 mantle, pale pearl-blue ; three first primaries mainly white ; first primary with 

 black outer web ; first six primaries have black ends, a half inch or over long and 

 each one is slightly tipped with white ; other primaries like back. In winter the 

 adult has white head with dark spots over ears, in other respects quite like adult in 

 spring. 



Young. Bill, black, yellowish at base ; tarsi, reddish-yellow (dried skin) ; 

 iris, hazel ; greater part of head, the throat, neck and under parts white ; tail, 

 white, except a black bar nearly an inch wide at end ; primaries with much more 

 black than in adult ; dark colored auricular spots ; crown and upper parts, espe- 

 pecially the wings, mottled with light lead color and brownish-gray ; length about 

 14 inches' ; extent about 32 inches. 



Habitat Whole of North America, breeding mostly north of the United States ; 

 south in winter to Mexico and Central America. \ 



This species known to fishermen on Lake Erie and about the Dela- 

 ware and Susquehanna rivers as " Little Gull," is by far the most abun- 

 dant of all the Gulls in Pennsylvania, where it occurs as a regular mi- 

 grant in the spring- and fall. During- migrations, particularly in the 

 autumn, these birds are frequently to be seen in considerable numbers 

 about the harbor at Erie city. Bonaparte's Gulls are found generally 

 throughout the state, about the numerous lakes, ponds and larger 

 streams. Occasionally in the interior good-sized flocks are noted, but 

 usually they are seen singly, in pairs, or sometimes in small parties of 

 four or five individuals. They generally arrive here early in April and 

 remain mostly until early in May, when they pass northward to their 

 breeding grounds, from which they -return here usually about the first 

 week in October and remain until early in November. At Lake Erie, 

 where the species is perhaps more numerous than in any other section 

 of Pennsylvania, I observed a flock of a dozen or more of these Gulls in 

 company with two or three Herring Gulls late in the month of Decem- 

 ber, 1889. This bird, in addition to feeding on fish and other kinds of 

 aquatic animal life, subsists, also, to a considerable extent, on different 

 insects, particularly beetles and grasshoppers. 



GENUS RISSA STEPHENS. 

 Rissa tridactyla (LINN.). 



Kittiwakc. 



DESCRIPTION. 



" Adult. Head, neck, entire under plumage, rump and tail, white ; back and 

 wings light bluish-gray ; the ends of the five outer primaries, and the outer web of 

 the first, black; the fourth and fifth have small white tips; bill, greenish -yel low ' 

 iris, reddish-brown ; legs and feet brownish-black, with a green tinge. 



