148 BULLETIN U3, UNITED STATES NATIONAL MUSEUM. 



Winter range. — From the British Isles south to the Canary 

 Islands, the Mediterranean Sea, northern Africa, the Nile Valley, 

 and the Persian Gulf, and on the Asiatic side to Japan and China. 



Casual records. — Has been taken once in North America (Henley 

 Harbor, Labrador), a young bird of doubtful identity. Records 

 from California refer to other species. 



Egg dates. — Great Britain: Twenty-two records, May 6 to July 

 18 ; eleven records. May 16 to June 1. 



LARUS HEERMANNI Cassin. 

 HEERMANN'S GULL. 



HABITS. 



Among the mixed flocks of large gulls which frequent the beaches 

 of southern California we frequently see a few and sometimes many 

 smaller gulls conspicious by their dark color and long legs. Some 

 seem to be wholly black or dark brown; these are the young birds, 

 which are present more or less all the year round. Others, with con- 

 spicuous white heads, are the adults; these are absent during the later 

 part of the spring and early summer, while on their breeding grounds 

 farther south. The species is very well marked and entirely unlike 

 any other species of Larus. It has even been placed by some writers 

 in another genus, Blasiyus.^ together with two or three other species 

 found in other parts of the Pacific Ocean, which its general ap- 

 pearance seems to warrant. It is different from other gulls also in 

 its migrations, being the only one of our gulls which migrates south- 

 ward to breed and northward again to spend the fall and winter. 



Courtship. — Mr. AVilmot W. Brown jr., has given us the only 

 account we have of the courtship of this species. He was fortunate 

 enough to arrive on the Island of Ildefonso, in the Gulf of Cali- 

 fornia, early enough to see it. I quote from his notes, published by 

 Col. John E. Thayer (1911), as follows: 



When I first arrived (March 2,4) there were an immense numher of birds. 

 The males were constantly seen fluttering .over the females on the ground, 

 near their nests; but no eggs were laid until April 2. It seems they spend 

 some tim.e in courtship before settling down to their matrimonial duties. The 

 female when in passion emits a peculiar squeaky sound as she coaxes the 

 male by squatting down and going through the most ludicrous motions. I 

 have also seen a pair holding on to each other's bills, a kind of tug-of-war 

 affair; then they would back away and go through a suggestion of a dance, 

 but all the time talking to each other in low love tones. The appearance of 

 a duck-hawk would send them all flying to sea. They would return, however, 

 very quickly. 



On the southeastern end of the island, facing the sea, there is a large semicircu- 

 lar shaped depression, which covers about 5 acres. It is quite level on the bot- 

 tom and covered with gravel, with here and there blocks of lava scattered about. 



