Bonaparte's gull. 543 



Their color is an olivaceous-drab, sometimes a grayish- 

 green. This is covered, more or less thickly, with blotches 

 and spots of different shades of brown and purple, and 

 obscure markings of the same. 



Their dimensions vary from 2.28 by 1.65 inch to 2 by 1.50 

 inch. Some specimens have numerous irregular streaks 

 of umber-brown over the surface at the greater end, and 

 others have large confluent blotches of the same color. 



CHROICOCEPHALUS PHILADELPHIA. — Lawrence. 

 Bonaparte's Gull. 



Larm Bonapartei, Nuttall. Man., II. (1834) 294. Aud. Birds Am., VII. (1844) 



131. 



Description. 



Adult. — Head and upper part of neck grayish-black, this color extending rather 

 lower on the throat than on the neck beliind; lower part of neck, under plumage, 

 rump, and tail, wliite; back and wings clear bluish-graj'; first primary black on the 

 outer web ; inner web of the first primary, both webs of the second, and the outer 

 web of tiie third, white; the inner web of the third, and all the other primaries, are 

 of the same color as the back; the six outer primaries have their ends black for the 

 extent of about an inch on the central ones, but less on the first and sixth, — they 

 are all slightly tipped with white; shoulders, anterior borders of the wings, and outer 

 webs of the primary coverts white; bill deep black; inside of mouth carmine; iris 

 hazel; legs and feet orange, with a reddish tinge. 



The 3'oung have tlie head white, intermixed on the occiput and hind neck with 

 dark-gra}'; a round spot of dark-plumbeous behind the ej'e ; the smaller wing 

 coverts brown ; the outer webs of several of the primaries, and a subterminal band 

 on the tail, black. 



Length, fourteen and a half inches; wing, ten and a half; tail, four and a quar- 

 ter; bill, one and one-eighth; tarsus, one and five-sixteenths inch. 



Hctb. — Texas to Nova Scotia, Mississippi River, fur countries, Pacific coast of 

 North America. 



This species is pretty common on our coast, and is often 

 found in the neighborhood of large tracts of water in the 

 interior. 



BISSA, Lkach. 



Rissa, Leach, Steph. Gen. Zool., XIII. (1825) 180. (Type Lnras tridactylu^, L.) 



Bill rather long, strong, and much compressed; culmen straight at base, curved 



from the nostrils to the tip ; nostrils lateral and longitudinal ; wings long and 



pointed; tail even; tarsi rather short; toes slender and united by a full web; him' 



toe rudimentary or very small. 



