LIFE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 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, mollusks, 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—tn 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 
ata 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 amore 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 fish 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. 
