LIFE HISTORIES OF NORTH AMERICAN DI\TNG BIRDS. 175 



Nesting. — The Bird Rock colonies have been so often described that 

 any lengthy account of them would be unnecessary repetition. At 

 the time of our visit, June 23 to 25, 1904, the total population of the 

 rock was estimated as about 10,000 birds. We thought that the com- 

 mon murres ranked about fifth in numerical strength, although not 

 far behind the Briinnich's nmrres in this respect. I estimated that 

 the common murres numbered about 1,400. The murres and Briin- 

 nich's murres were nesting in mixed colonies, arranged in long rows 

 along the narrower ledges, such as were not available for gannets. 

 The eggs were generally inaccessible, except with the aid of a rope, 

 :and were mostly on the lower or middle sections of the cliffs, but 

 there were some wdiich we could reach by going down the ladders 

 4ind climbing around on the broader ledges. Here the eggs were 

 laid on the bare rock or on the loose soil accumulated by disintegrat- 

 ing rock; they were laid in rows, about as close as the birds could 

 sit, and usually with the smaller end pointing outward. Nearly 

 every one who has written about the eggs of the murres has called 

 attention to their pyriform shape, which is supposed to cause them 

 to roll in a circle, when disturbed, instead of rolling off the ledges; 

 but anyone who has had much experience in murre rookeries knows 

 that any sudden disturbance, which frightens the birds off their 

 nests, generallj^ results in a shower of eggs, showing that this theory 

 •does not always work out in practice. 



On the flat rocky islands off the south coast of Labrador the murres 

 evidently nested in compact open colonies, as is often the case with 

 the California murres. Such colonies were much more easily robbed 

 of their eggs than the cliff colonies, which would account for their 

 rapid extermination. Dr. Townsend writes nie, in regard to one of 

 the islands he visited near Cape \Vhittle : 



On one of these, Outer Islana, off Coacoacho Bay, besides the nests of some 

 600 pairs of double-crested cormorants, were about a tliousarfd eggs of murres. 

 The combined colony of these two species was crowded together on about an 

 acre of the summit of the small rocky island. The large nests of the double- 

 crested cormorant occupied every available site, and the eggs of the nmrres 

 were thickly scattered between the nests. This was on July 14, and nearly 

 all of the cormorant eggs had hatched and the young in various .stages were 

 clamoring for food. None of the murres' eggs had hatched, some were fresh, 

 but the majority were cou.siderably incubated. As we landed on the i.3land 

 most of the adult cormorants took to flight but the murres allowed a close 

 approach, and, as we walked among them, they shuffled out of the way, walking 

 almost erect and moving their small wings like arms. Every now and then 

 they would fall over on their bellies, and they often launched themselves head- 

 long over the rocks in their efforts to take to wing. Everything was daubed 

 with excrement, the nests, rocks, and eggs. Most of the murres' eggs were so 

 covered with the filth that their beautiful markings could not be seen, and the 

 birds themselves had sadly soiled their white breasts. I counted a hundred 

 «ggs in the .space 10 feet squai'e. 



