402 PETRELS AND SHEARWATERS 



scudding the pinions are held very straight, a fact which enables the 

 fulmar to be distinguished from the gull with ease. Large pieces of 

 food which may be thrown out to them are torn in pieces as the bird 

 sits paddling in the water, smaller pieces are swallowed at once, some- 

 times in mid-air. But they seem to dive but rarely, and even then 

 the plunge is but momentary. If all accounts are true, however, they 

 go deep enough to reach the bait of "long-liners." Curiously enough, 

 during this short sojourn on land, when breeding, these birds display 

 a strange liking for the sorrel which grows on the ledges where they 

 are breeding. But save during this short space of time no other 

 vegetable food is eaten. 



Of the behaviour of these birds during the "courtship" period 

 there are few records, and by far the most lengthy are those of Mr. 

 Selous, who studied the fulmar in the Shetlands. After the birds have 

 mated, it would seem they indulge in strange and often grotesque 

 antics. One of the most curious is a habit of facing one another 

 open-mouthed, and with outstretched necks, meanwhile moving the 

 head from side to side and up and down as they utter a series of 

 hoarse coughs or grunts, though at times they perform in silence. 

 This display of the open mouth seems designed to make the most of 

 the delicate mauvy-blue which lines its cavity, yet it is surely more 

 than doubtful whether either bird exactly realises that its own mouth 

 is coloured like that of its neighbour; though nevertheless the exhibi- 

 tion of it may serve as an excitant. It is certainly significant that this 

 parade of the open mouth is only seen in such species as have this 

 cavity brilliantly coloured, as, for example, in the black-guillemot, the 

 razorbill, and the shag. 



Since the young petrel in its fledgling plumage scarcely differs 

 from the adult, it is not surprising to find that the mouth cavity is in 

 like manner coloured, but it differs in hue, being paler and pinker. 



Both sexes seem to share in the duties of incubation of the single 

 egg and in feeding the chick, which for some considerable time 

 remains in a lethargic state. Only once in a while, remarks Mr. 



