THE TUBE-NOSES igi 



When first hatched the chick's body-temperature is about io°C 

 below that of the adult. It therefore needs the warmth of its parent's 

 body (about 38.8°C in the case of Wilson's petrel), until its own 

 temperature-regulating mechanism, aided by a plentiful down, is 

 developed; this occurs towards the end of the first week, when it 

 'emerges' from its parent's incubation-patch; whereupon, it is aband- 

 oned by the day and not ever brooded by the adult again, although 

 occasionally an adult will remain by day in the nest, sitting beside 

 the chick quite late in the rearing period. 



Wilson's, Leach's and storm-petrel chicks, born in cool latitudes, 

 are feeble and blind when born and develop slowly. The chick of 

 Bulwer's petrel, on the contrary, born in the warm latitudes, has its 

 eyes open and is extremely active. It grows rapidly. It has no bald 

 spot on the crown as have the storm- and frigate-petrels. 



After the first week, then, the regular attention (one might justifiably 

 say, the Gropyrj of the parents for the new-born) which the chick has 

 received suffers a gradual change. It was first fed a few hours after 

 hatching and again several times during the first twenty-four hours 

 (Richdale, 1943, p. 113, on the frigate-petrel), so long as the adult, 

 with ample reserves of "oil" in its crop, was there to brood and care 

 for it. But once (aided by good feeding) it has reached the homio- 

 thermic stage it is left alone by day. The adults (of some species at least) 

 now go farther to sea, seeking solid food, and do not return at all on 

 some nights. Ringing of breeding Manx shearwaters has shown 

 (Lockley, 1942) that the adults, with mates on eggs at Skokholm, may 

 travel as far south as the Spanish coast, six hundred miles distant, to 

 feed (principally on sardines — they are shot or caught by Basque 

 sardine fishermen) ; this voyage of one thousand two hundred miles 

 there and back could not be accomplished in less than two days, and, 

 allowing time for feeding, probably longer. Incidentally the value 

 of this patient ringing of several thousands of these birds on their 

 remote breeding island was never more obvious than in the proof of 

 this amazing journey of the breeding shearwaters. 



During the latter half of the eight to ten weeks of the fledging 

 period, feeding becomes more and more intermittent. During a 

 moonlit period several nights may elapse without the Manx shearwater 

 chick being visited. The burrows of \Vilson's petrel are often blocked 

 by snow, for several days, but even when clear of snow they are not 

 regularly visited; and the unfed nestlings lose weight. The chick of 

 Leach's petrel is fed irregularly; it has even been suggested that the 



