lO 



PETRI- L GROUP 



In addition to the dccpl>- forked tail from which it takes one of 

 its names, Leach's petrel, which has the general sooty plumage of 

 mo^ of its relatives and measures 8 inches in length, is specially 

 characterised by the black legs, the smoky grey middle and greater 

 wing-coverts passing into white on the edges of the greater coverts 

 and innermost secondary quills, the short white tips to the scapulars, 

 the white upper tail-coverts, and the presence of a white patch on each 

 side of the under side of the tail. Immature birds cannot be distin- 

 guished from the adults in colour. The long down of the chick differs 



.MAUKIK.V rKTKKL. 



from that of the nestling storm-petrel by being uniformlj' greyish 

 brown in place of black. 



In St. Kilda these petrels breed on the flat ground at the summit 

 of the cliffs in the neighbourhood of the capital town, each bird laj-ing 

 its single egg at the bottom of a burrow of considerable depth ; several 

 of such burrows being often found in proximity, and some of them 

 having two entrances. During their sojourn on land these petrels, 

 like many others of the tribe, are largely nocturnal, keeping within 

 their holes during the day-time. Both birds take their turn at 

 incubation ; but it is somewhat remarkable that onh' a single bird is 

 reported to be found in each hole, thus leaving unexplained what 

 becomes of the individuals off dut\'. The egg is slightly larger than 

 that of the storm-petrel, and usually shows a ring of pale lilac specks 

 at the large end. 



