72 BULLETIN 113, UNITED STATES NATIONAL MUSEUM. 



but Mr. Dawson's (1908) reference to the large number of 

 " mulattoes " on Carroll Islet suggests the possibility that these 

 two species may hybridize. 



Mr. Dawson (1909), who spent a week studying the vocal per- 

 formances of this species and their significance, has thus classified 

 its various notes : 



1. The beak-quaking notes — Harsh, unmusical, and of moderate pitch, used 

 to express distrust and continued disapproval. During the delivery the 

 mandibles are brought together three or four times in moderate succession. 

 This is the ordinary scolding or distress cry of characteristic and uniform 

 pitch, save that it is raised, to a higher, key when- the speaker becomes 

 vehement. The phrase varies from three to five notes, and is uttered in the 

 following cadences : Jcak-ako; ka ka, lea ka; ka ka fcofca/ kaka; kaka, 

 ka kakak; kak-a kak-a-ka. 



2. Kawk. — A note of inquiry or mere communication ; has many modifications 

 and varies from a short trumpet note to the succeeding. 



3. Klook. — A sepulchral note of uniform interest but uncertain meaning. 



4. The trumpet notes, long or short, single or in prolonged succession, high- 

 pitched, musical, and far-sounding. During delivery the head is thrust for- 

 ward, the neck arched, and the throat and mandibles opened to their fullest 

 capacity. These are pleasure notes and are used especially on social occasions, 

 when many birds are about, keer, keer, keer, keer. 



5. A(n)k, a(n)k, a(n)k, a(n)k, a(n)k, a(n)k. — Minor trumpet notes of regu- 

 lar length andl succession, used in expostulation or social excitement ; frequent 

 and varied. 



6. Klook, klook, klook. — In quality a combination of kawk and the trumpet 

 tones, uttered deliberately and without much show of energy. Used chiefly in 

 domestic conversation of uncertain import 



7. Oree-eh, oree-eh, oree-eh, an an an. — An expression of greeting as when 

 uttered by a sitting bird welcoming one about to alight The notes of the first 

 series are trumpet tones, in which the second syllable of each member is raised 

 to a higher pitch, while the voice is dropped again on the third. The second 

 series is lower and more trivial, but still enthusiastic, as though congratulatory 

 to the guest arrived. 



8. Ko, — Shouted once, or thrice repeated, in quelling a clamor. " Hist ! Hist ! 

 You're making too much noise ; he's watching us." 



9. Arahh. — A slow and mournful trumpeting, usually uttered awing, to ex- 

 press anxiety or grief, as at the loss of a chick. 



10. Oo anh, oo anh. — Repeated indefinitely. Notes of coaxing and endear- 

 ment usually addressed to children, but occasionally to wedded mates. The 

 cooing of doves does not express so much adulation or idolatrous devotion as 

 the gull throws into these most domestic tones. 



Winter. — When winter, with its snow and ice, drives the glaucous- 

 winged gull from the northern portion of its breeding range, there 

 is a general movement southward ; but the migration is more in 

 evidence along the California coast, where this species spends the 

 winter in large numbers, frequenting the harbors in company with 

 glaucous, herring, California, western, and short-billed gulls. It 

 winters commonly as far north as the Aleutian Islands, where it can 

 always find open water. 



