LIFE HISTORIES OF NORTH AMEBIOAK DIVING BIBDS. 171 



is acquired ; this molt is very much prolonged or variable, beginning 

 often in February, sometimes in January, and lasting well into 

 June. I have in my collection birds in full nuptial plumage, taken 

 as early as May 2, and birds still showing many white feathers, taken 

 as late as June 15. The postnuptial molt in adults is complete; 

 it begins before the middle of August and is usually completed 

 during September. * 



Food. — The food of the pigeon guillemot seems to consist of small 

 fish, moUusks, Crustacea, and other marine animals which it obtains 

 by diving as well as on the surface. Doctor Grinnell (1910) speaks 

 of seeing one flying about its nesting site, " with a long yellow 

 marine worm hanging from her bill." 



Behavior. — In flight or on the water the pigeon guillemot closely 

 resembles the black guillemot, the only distinguishing mark being the 

 black wedge in the white wing patch, which is not very conspicuous 

 at a distance. It flies swiftly and strongly, usually close to the water, 

 and seems to prefer to fly out and around an approaching boat in a 

 circle. It is a good diver and " flies " under water, using only its 

 wings for propulsion, with its conspicuous red feet held straight out 

 behind, probably to help it in steering. It swims buoyantly and 

 gracefully, frequently with its head below the surface, as if feeding 

 or looking for food. It congregates in small parties on the low 

 rocks near the shore, to bask in the sun or to rest, where it stands 

 nearly upright with its tail resting on the rock or sits upon its 

 breast in a more restful attitude. Its feet are strong enough for it to 

 stand upon and it can walk about quite freely. 



The only notes which I have heard it utter are a faint, shrill, 

 whistling call note and a hissing note of angry protest when dis- 

 turbed on its nest. Nelson (1887) says: 



Their common note is a low piping whistle, and Dr. Bean heard them utter- 

 ing calls like the chipping of a sparrow. 



The pigeon guillemot is associated on its breeding grounds with a 

 great variety of other species, practically all of the seabirds of the 

 Pacific coast, among which it seems to be always a peaceful and harm- 

 less neighbor. It never seems to disturb the eggs or young of other 

 species. Its own eggs and young are usually too well concealed in 

 the crevices among the rocks for the gulls to find them. Accord- 

 ing to Prof. Harold Heath (1915), these birds suffer greatly from the 

 depredations of the northwestern crow, on Forrester Island, Alaska, 

 for he observed that — 



Out of six pairs only one succeeded in hatching a brood, and cracked and 

 punctured shells indicated the culprit. The natives report that the flsh crow 

 destroys the eggs of every species of birds where nests are exposed, and they 

 declare it to be fully as great a pest as the eagle. 



