The Nesting of the Storm Petrel 



which had for some reason proved unfertile. This was in- 

 teresting, as showing that the storm petrel is in the habit of 

 using the same nesting hollow each season, and, indeed, in 

 several other nests that I examined I found, lying beside the 

 ^g^ or young, portions of eggs of previous years. 



During a subsequent season I had an opportunity of 

 further investigating the breeding of these small petrels. 



On August 1 8, a day when the high tops were snow- 

 capped and the north wind already had in its breath a fore- 

 taste of winter, I marked one of the petrels which was 

 brooding on a very hard set ^gg, which would have hatched 

 in a few days' time at the outside. On October 13, 

 exactly eight weeks later, I again visited the lonely island. 

 After much rough and unsettled weather, mid-October 

 brought summerlike conditions to the Hebrides. After a 

 quiet sail the petrels' island was reached, and in the nest 

 marked in August I was interested to find the young storm 

 petrel, at first glance almost indistinguishable from an adult 

 bird. On removing it, however, I found that on the whole 

 of its under-parts the grey down still remained, though 

 beneath it were the fully-grown feathers. There persisted 

 small tufts of down on the scapulars also and on the back. 

 A curious point was that its mouth had down adhering to 

 it, st^eming to show that the nestling had been engaged 

 in pulling out its downy coat. 



With the exception of a noticeable crest on its forehead, 

 its plumage, even down to the conspicuous white rump, 

 seemed to be entirely similar to that of its parents. This was 

 interesting since few birds assume the adult dress before 

 leaving the nest. As far as could be judged, this bird would 

 have been ready to leave the nesting cranny in a week or ten 

 days' time, so that, assuming the ^gg hatched within a week 

 of August 18, the youngster must have remained a full eight 

 weeks in the nest, probably a few days longer. 



How protracted a period of fledging is this as compared 

 with the house martin, a bird of a similar size, which remains 



75 



