LITE HISTORIES OF NORTH AMERICAN DIVING BIRDS. 167 



Bowdoin Bay, September 6; and eastern Greenland, latitude 78° 20', 

 September 3. 



Egg dates. — Hudson Bay : 6 records, June 10 and 21, July 6, 7, 10, 

 and 24. Cumberland Gulf : 2 records, June 28 and July 2. Green- 

 land : 1 record, July 4. 



f 



CEPPHUS COLUMBA (Pallas). 



PIGEON GUILLEMOT. 



HABITS. 



From the painted caves of the Santa Barbara Islands northward 

 to the bold rocky islands of northern Bering Sea we found the pigeon 

 guillemot, the Pacific coast representative of our familiar " sea pig- 

 eon," everywhere common in the vicinity of rocky shores or high 

 precipitous cliffs, where it finds congenial summer homes. South of 

 the Aleutian Islands and the Alaska Peninsula it is present through- 

 out the year, but there is a decided migratory movement north of 

 this line and probabl}^ a less noticeable migration throughout its 

 range. 



Spring. — From its Avinter wanderings, at sea or along the coast, it 

 returns in early spring to its breeding grounds. In the Commander 

 Islands, according to Stejneger (1885), this occurs as early as the 

 middle of March, and farther north as soon as open water can be 

 found. On their arrival at their breeding grounds the birds con- 

 greate about their favorite nesting sites, but are in no hurry to begin 

 laying. Egg laying does not begin on the California coast much 

 before the middle of May, and in the Aleutian Islands not before 

 the middle or last of June. During the mating season the males 

 indulge in many little squabbles and even vigorous combats. Daw- 

 son (1909) describes the encounter as follows: 



A cockfight between rival suitors is apt to be quite a .spirited affair. As 

 they face each other upon the surface of the water, the combatants hold their 

 tails, inconspicuous at other times, bolt upright; and this, with their open 

 mandibles disclosing a bright-red mouth and throat, gives the birds a some- 

 what formidable appearance. The actual scrimmage, however, is likely to take 

 place beneath the water rather than upon it ; and the onlooker has no means of 

 guessing the battle's progress till the weaker bird bursts from the water like a 

 flying fish, and so by change of scene gains a momentary advantage of his 

 pursuer or owns defeat outiight. 



Nesting. — In the precipitous rocky cliffs of the Santa Barbara 

 Islands are numerous large, deep caverns, worn away by the action 

 of the waves, which have for unknown ages been pounding at the 

 foundations of these solid walls of rock and carved them into fan- 

 tastic shapes. At high tide or in rough weather most of them are in- 

 accessible, but under favorable circumstances some of them can be 

 explored in a boat or even on foot in safety. In the " painted caves '^ 



