LIFE HISTORIES OF NORTH AMEIU(;AN PETRELS AND PELICANS. 219 



notes on what he calls the courtship dance, although, at the time of his 

 (observations, the breeding season was well advanced, lie says: 



I spent many hours in the summer of 1919 un<ler most favorable conditions 

 nf'.-ir the great gannet nesting ledges on the clifis of Bona venture Island; I saw 

 the dunce repeated i>y hundreds of pairs many times and I came to the same 

 cfmclusjon that Professor Fisher did in the case of tlie liUysan albatross, namely, 

 that It was originally a courtship dance and that it was continued from habit 

 and from the joy of it, in the same way that the song sparrow continues to 

 sing long after the nesting season. 



Let me describe a typical performance: As the sexes are alike in plumage, 

 they can not be distinguished apart. One of them — we will assume it is the 

 male — is swinging around in great circles on rigidly outstretched and motion- 

 less wings. lie passes within a few yards of me and swings toward a shelf 

 crowded with birds brooding their downy black-faced young. Alighting on the 

 edge, he elbows his way along the shelf, notwithstanding the angry looks, the 

 black mouths sudd<'iily opened, and the vicious pecks of his neighbors. All of 

 these he returns in kind. Arrived at the nest, he is enthusiastically greeted 

 by his uiatci, who, disregarding the young bird beneath her, ris*(JS up to do her 

 part in the dance. The birds stand face to face, the wings .slightly raised and 

 open(.'d, tlie tail elevated and spread. They bow towards each other, then 

 raise their heads and wave their bills as if they were whetting these powerful 

 Instruments, or as if they were performing the polite preliminaries of a fencing 

 Ijout. From time to time this process is interrupted as they bow to each other 

 and appear to caress each otlier as each dips its pale-blue bill and cream- 

 colored head first to one side and then to the other of its mate's snowy breast. 

 With unabated enthusiasm and ardor the various actions of this curious and 

 loving dance are repeated again and again, and often continue for .several 

 minutes. After the dance the pair preen themselves and each other, or the 

 one first at the nest flies away, and the new arrival waddles around so as to 

 get back of the nestling, and the strange process of feeding takes place. 



This dance is not only performed by pairs, as first de.scribed, but not infre- 

 quently individuals perform a pas seul; it may be because he or she is wearied 

 with waiting for its mate. The wings are slightly raised and opened, the tail 

 elevated and spread, the bill pointed vertically upwards and waved aloft, then 

 flipped to one side under the half-open wing and then to the other, the bill 

 raised and waved again, and so on over and over again. Owing to the great 

 volume of .sound from the le<lges, it is impossible to distinguish any individual 

 performer, and I was unable to tell at what point in the dance and to what 

 extent the song was important. The sound is like that of a thousand rattling 

 looms in a great factory, a rough, vibrating, pulsing sound — " car-ra, car-ra, 

 car-ra." 



Nesting. — An account of the nesting conditions as we saw them 

 on Bird Rock and on North Bird Rock, wall serve to illustrate the 

 two common methods of nesting, which are ahso typical of the species 

 elsewhere. On Bird Rock the nests were all on the ledges on the 

 sides of the rock; the broader ledges were well covered with nests 

 several rows deep, and many smaller shelves were occupied by as 

 many nests as they could hold. The nests varied greatly in size 

 and in style of construction from practically nothing to well-made 

 nests 18 inches in diameter and 5 inches high; probably the nests 



