254 LONG-WINGED SWIMMERS — LONGIPENNES. 



this species breeds on the Coronados Islands, Dr. Cooper remarks that it probably 

 breeds on other island groups on the coast south of San Francisco. 



These birds are common as far north in the summer as the Straits of Fuca, but 

 come south to the Columbia in winter. The young-plumaged birds are very constant 

 attendants on the flocks of Pelicans, and rob the latter of a portion of the fish which 

 these bring up in their scoop-like pouches, seizing upon those which fall out or hang 

 outside, the Pelicans never resenting this treatment. Audubon ascribes the same 

 habit to the Black-headed Gull in Florida. 



At San Diego Dr. Cooper did not observe that this species followed the Pelicans 

 so much as it does at the north. It is almost exclusively a fish-eater, and is known 

 to dive for this food. It is also very much given to frequenting the fields of kelp 

 which fringe the shores, at a distance of from one to three miles, where it finds small 

 Crustacea and mollusca. In one instance only did he see one of t'his species feeding 

 on the carcase of a bird, and this was a bird which he himself had thrown away. This 

 Gull also follows vessels in or near the bays, but never accompanies them far to sea, 

 although its flight is very rapid. Dr. Heermann mentions having once seen this 

 species feeding on a dead seal. 



According to Dr. Newberry, this species is common as far up the Sacramento as 

 Feather River ; but Dr. Cooper never saw it far from the salt water. Its voice is 

 said to be faint, and rather querulous ; and it is rarely heard except when the bird 

 is fishing. 



Colonel Grayson met with this species on the Pacific coast near Mazatlan, in 

 Western Mexico, and also on the Island of Isabella ; but it was not common there. 

 In the neighborhood of Mazatlan it occurred chiefly as a winter visitor. Specimens 

 were shot on the sea-beach near that city in February and March. An egg of this 

 species collected by Colonel Grayson on an island near Mazatlan (Smithsonian Insti- 

 tution, No. 15519) is of a rather oblong oval form, tapering toward one end, and 

 rounded at the other. It measures 2.35 inches in length by 1.65 in breadth. Its 

 ground-color is a light clayish-drab, over which it is marked with bold spots of lilac- 

 gray and two different shades of sepia-brown. Another egg in my collection — pro- 

 cured from the Farallones by Mr. George F. Faulkner — measures 2.27 inches in length 

 by 1.55 in breadth. Its ground-color is a deep drab, and the markings are large 

 blotches of dark bistre, approaching to blackness. These are scattered over the 

 surface of the egg, and are of rounded shape about the smaller end, and more irregular 

 in shape, and more confluently grouped together, about the larger end. The obscure 

 shell-marks of lilac are few and scattered. 



Larus atricilla. 



THE LAUGHING GULL. 



Larus atricilla, Linn. S. N. ed. 10, I. 1758, 136; erl. 12, I. 1766, 225 (based on Zarus w!rr;or, 

 Catesb. 1. 89, but also includes the Euroi)ean species, L. ridihmdm, Linn.). — Nutt. Man. IL 

 1834, 291. —AuD. Orn. Biog. IV. 1838, 118, pi. 314; Syuop. 1839, 324; B. Am. YIL 1844, 

 136, pi. 443. — CouEs, Key, 1872, 315 ; Check List, 1873, no. 554. — Saunders, P. Z. S. 1878, 

 194. — RiDGW. Nom. N. Am. B. 1881, no. 673. 



Larus {Chroicocephalus) atricilla, Brucii, J. f. 0. 1853, 106. — CouES, B. N. W. 1874, 650. 



ChroicocejyJialus atricilla, Lawr. in Baird's B. N. Am. 1858, 850. — Baird, Cat. N. Am. B. 1859, 

 no. 667. — CouEs, Pr. Ac. Nat. Sci. Pliilad. 1862, 310 ; 2d Check List, 1882, no. 786. 



Larus ridibundus, WiLS. Am. Orn. IX. 1814, 89, pi. 74, fig. 4 (not of Linn.). 



Larus plumbiceps, Breiim, Lchrb. 722 (Gray). 



Larus {Atricilla} mcgaloplcrus, Buucii, J. f. 0. 1855, 287. 



