58 BULLETIN 113^ UNITED STATES NATIONAL MUSEUM. 



Behavior.— The flight of this gull is not especially different from 

 that of other large gulls, though it is particularly strong and at times 

 quite swift, as when chasing the smaller sea birds to rob them of 

 their food. The white-tipped wings serve to distinguish it from all 

 other gulls except the Iceland gull, from which it differs only in 

 size — a very unsatisfactory field mark. Even in young birds the pri- 

 maries are much whiter than in other species, so that on the Pacific 

 coast the glaucous gull can usually be recognized at short range. 



Its voice is usually Joud and harsh, often shrill and penetrating, 

 but on its breeding grounds I have heard it utter a variety of soft 

 conversational notes after the first excitement was over. Nelson 

 (1887) gives us a good description of its notes as follows : 



They have, a series of hoarse cries like the syllables ku-ku-ku, ku-lee-oo, 

 ku-lee-oo, ku-lee-oo, ku-ku-ku, ku-ku-ku. The syllables ku-ku are uttered in a 

 hoarse nasal tone ; the rest, in a shrill, screaming cry, reaching the ear at a 

 great distance. These notes are used when quarreling or communicating with 

 each other, and when disturbed on their breeding ground. At Unalaska, dur- 

 ing May, 1877, 1 found them about the cliffs on the outer face of the island, and 

 ■they protested < vigorously against our presence as they glided back and forth 

 overhead or perched on craggy shelves. 



Elliott (1880) says: 



It has a loud, shrill, eaglelike scream, becoming more monotonous by its 

 repetition ; and it also utters a low, chattering croak while coasting. 



Turner (1886) observes: 



The note of this bird is variable ; in spring a harsh Kaou, which changes to a 

 deep honk, in a few weeks. When flying along the shore a prolonged, grunting 

 croak is uttered. 



Chamberlain (1891) gives it as " something like the syllables Kuk- 

 lak; I have seen it written cut-XeekP 



I quote from Mr. Hersey's notes his observations on the behavior 

 of this species near St. Michael: 



The glaucous gull is a bird of marked individuality. , Though, often solitary, 

 when a number do assemble together they are usually' rather noisy. A large 

 flock has kept close to the ship for several days while we have" been anchored 

 in the bay and this gave me a good opportunity to study them. Often while 

 all were resting quietly on the water pne would extend his neck, open his 

 mouth to its widest extent, and swim rapidly along, voicing, his wild harsh 

 notes. Sometimes he would swim in circles while calling, or two birds 

 would swim side by side, either in a straight course or circling. At other 

 times they would face one another on the water, or when on the wing one 

 would rise above the other, the lower bird stretching his neck up and the 

 other reaching downward, and both with dangling legs and motionless wings 

 cry lustily. At one time while two birds were struggling with a piece of 

 food two others sat on the water near by and added their cries to the general 

 commotion. Both adult and immature birds do this. 



They are strong swift fliers, and probably pugnacious toward smaller or 

 weaker species, but I did not see them molest any other birds,, although 



