( 175 ) 



FURTHER NOTES ON THE NESTING OF THE 

 STORM-PETREL.* 



BY 



AUDREY GORDON. 



Owing to the exceptionally stormy summer of 1920 there was 

 little opportunity of visiting the almost inaccessible Hebridean 

 Islands which are the haunt of the Storm-Petrel {Hydrohates 

 peldgicus). But on August i8th one nest was found with the 

 egg within a few days of hatching. The island on which this 

 nest was situated was again visited on October 13th, exactly 

 eight weeks later, and the nest was found to contain an almost 

 fully fledged young Petrel. The nestling was fully feathered 

 on the upper parts, but tufts of down still adhered here and 

 there. The under parts were thickly covered with long 

 down, about an inch in length. Under this, however, the 

 feathers were partly grown. The bird's beak had a good deal 

 of down sticking to it, as though it had been engaged in freeing 

 itself of down. In all probability it would be ready to leave 

 the nest in a week's time, say about October 20th. This 

 seems to show that the young of the Storm-Petrel remain in 

 the nest between eight and nine weeks. The hatching of the 

 egg has been proved to take at least five weeks, so the whole 

 period of nidification occupies thirteen or fourteen weeks. 



Three other young Petrels were found the same day. Two 

 were approximatel}^ the same age as the last mentioned, but 

 the other was not more than three weeks old, the wing- 

 feathers just beginning to appear. This means it would not 

 be ready to fly till the last week in November. As there is 

 practically no nest, and the young bird not far enough below 

 the surface of the ground to be sheltered from the wind, it is 

 difficult to believe how they can live so late in the year, 

 especially as the parent birds apparently never brood them 

 either by night or day after they are a week old. Yet one 

 never finds remains of dead young birds in the nesting crevices. 



The plumage of the three oldest Petrels exactly resembled 

 that of the adults, and lacked the white markings on the 

 wing and tail-coverts described in bird books. 



Besides these four young ones seen, several empty " nests " 

 were noticed, showing that a few young birds had already 

 flown, but, as in the Hebridean Islands, no eggs seem to be 

 laid before the beginning of July, probably none leave the 

 nest till about the first week in October. 



* For previous notes see British Birds, XIII., pp. 232-4. 



