LIFE HISTOKU-,S OF NORTH AMEBICAN DIVING BIEDS. 169 



above. I also noticed a number of pairs nesting under the wooden platform 

 that overhangs the rocks at North Landing. It Is usually several days after 

 laying the first egg before the bird lays the second. 



In the Puget Sound region the pigeon guillemot has frequently 

 been found nesting in high cliffs or clay banks, sometimes 200 feet 

 above the sea, where it excavates its own burrows. Dawson (1909) 

 writes: 



In excavating a tunnel In a claybank the bird uses beak and claws and Is 

 forced at the outset to maintain herself in midair, a task which, by reason of 

 her shortened wings, she accomplishes with no little exertion and Infinitely 

 less grace than that, say, displayed by a bank swallow. Not infrequently the 

 bird encounters a bowlder a few Inches In, and then the task is all to do over 

 again. If, however, excavation has progressed sufficiently, the tunnel is 

 continued at right angles. These tunnels are driven at any height which 

 pleases the pigeon's fancy, and most of them are accessible only by rope, 

 although Mr. Bowles records an instance near Tacoma of a tunnel which was 

 placed only 2 feet above the beach line. Incubation lasts a little over threfe 

 weeks, and eggs are oftener hatched after the lOth of July than before that 

 date. The same burrows, if undisturbed, are used year after year. 



Throughout the whole length of the Aleutian chain the pigeon 

 guillemot was one of the common birds, sitting in little groups on 

 the kelp-fringed rocks about the harbors or flying out around us in 

 circles to satisfy its curiosity. We found it nesting during the 

 latter half of June under the piles of loose rocks and bowlders along 

 the shores, at the bases of rocky cliffs, as well as in the crevices in 

 the rocks above. Farther north, on the rugged headlands of St. 

 Matthew and Hall Islands, we saw a few pigeon guillemots flying 

 out from the crevices in the lofty cliffs or sitting in little groups 

 on the ledges among the puffins, auklets, and fulmars. They were 

 undoubtedly nesting here in the inaccessible crevices in the rocks, 

 where the nests of all these species were beyond our reach. 



Some observers state that the guillemot gathers small stones to 

 line its nest, but this hardly seems likely ; perhaps it may prefer to 

 select hollows in which such small stones have accumulated, but 

 it frequently lays its eggs on the bare rock or ground or in whatever 

 debris it happens to find in a suitable cavity. It may scrape together 

 into a pile what material is available within easy reach, but I doubt 

 if it actually brings in any new material. The pigeon guillemot 

 regularly lays two eggs; generally several days intervene between 

 the laying of the first and second eggs, during which time incubation 

 is going on. 



Eggs. — ^The eggs of the pigeon guillemot closely resemble those of 

 the black guillemot, but they average slightly larger and are usually 

 more heavily and more handsomely marked. The shape varies from 

 pointed ovate to elongate ovate. The ground color varies from 

 "pale glaucous green" to greenish white, bluish white, or pure 



