104 BULLETISr 107, UNITED STATES NATIONAL MTTSEUM. 



CEBORHINCA MONOCEBATA (PalUa). 



BHINOOEBOS ATTKLET. 



HABITS. 



This curious auklet, the largest of its group, is a bird of our more 

 northern Pacific coast; it is not so well known, as its abundance at 

 certain points should justify, because of its nocturnal habits on its 

 breeding grounds ; like the petrels it is seldom seen by daylight except 

 when unearthed in its nesting burrow. It is essentially a bird of the 

 open sea, seldom entering the straits and inside passages and never 

 coming onto the land except to breed, coming and going during the 

 hours of darkness. 



Nesting. — One of the principal breeding resorts of this species is 

 Destruction Island, off the coast of Washington, which Mr. W. Leon 

 Dawson (1908a.) has described as — 



a flat-topped island with sharply sloping or nearly perpendicular sides, rising 

 60 feet above tide. Covered by dense grovs^th of vegetation, chiefly salmonberry 

 and salal thickets growing to height of a man's head, or higher on top ; same 

 with grass and bushes of other sorts on sides. Composed of deep loam (guano?), 

 clay, gravel (incipient conglomerate of Pleistocene age) in descending series, 

 resting unconformably upon the upturned edges of Miocene sandstone. Exten- 

 sive area of sandstone reefs exposed on all sides of island at low tide, includ- 

 ing ribs and ridges of sculptured rock unreached by water save in time of 

 storm. 



He estimated that about 10,000 rhinoceros auklets were nesting on 

 this island. 



Mr. Dawson (1909) has given us the following attractive account 

 of the arrival of these auklets on the island : 



Late in April the auklets, stirred by a common impulse, muster from the 

 wide seas and move upon Destruction by night. If there has been any scouting 

 or premature development work, it has been carried on by night only and has 

 escaped observation. In fact, it is a point of honor among the auklets never 

 to appear in the vicinity of the great rookery — or aukery — ^by day. At the 

 tribal home-coming, the keepers tell us, there is a great hubbub. If the location 

 be a brushy hillside, the birds upon arrival crash into the bushes like meteors 

 and take chances of a braining. Upon the ground, they first argue with old 

 neighbors about boundaries. If growls and barks and parrot-like shrieks mean 

 anything, there are some differences of opinion discovered. Perhaps also the 

 details of matrimony have not all been arranged, and there is much screaming 

 avowal. 



Gradually, however, order emerges from chaos, and the birds set to work 

 ■with a will renovating the old home or driving new tunnels in the loam, 

 sand, clay, or even hardpan. The burrows are usually 5 to 8 feet in length 

 and about 5 inches in diameter, terminating in a dome-shaped chamber a 

 foot or more across and 7 or 8 inches high. Each tunnel has a spur or blind 

 alley which, presumably, is occupied by the male during the honeymoon. For 

 lining, the nuptial chamber boasts nothing more pretentious than a few dead 

 salal leaves and a handful of dried grasses. The amount of labor involved in 

 this home-delving is very considerable. My guide once took an egg from a 



