MONOGRAPH OF THE PETRELS. 



kind of mouse-hole. This, by dint of long and tedious picking with a sheath-knife, 

 we enlarged till it admitted an arm up to the shoulder. The work was laborious, as the 

 floor of the burrow was hard black ice and grit, but eventually we reached the nest. 

 At the end of the little tunnel was a chamber containing a very comfortable nest thickly 

 lined with Adelie Penguin's feathers, and in it a somewhat remarkable collection. First 

 we brought out an adult male alive, then an adult female ; then two eggs, one clean 

 and newly-laid, the other old and rotten, and under all another dead and flattened 

 adult Oceanites. Outside, as we worked, a fourth bird was hovering, which, when shot, 

 proved to be an adult male. It has been long known that with this species the nesting 

 burrow has been often used by more than a single pair." 



It will be noticed that Dr. Wilson mentions a decayed body of one of these birds 

 being found in the nest, as well as an addled egg. It seems probable that more than 

 one pair inhabit the same breeding site, as Mr. Bernacchi speaks of finding five eggs 

 in one nest, but not all of them fresh. In the South Orkneys, writes Mr. Eagle Clarke 

 (I. c), " they appear to return year after year to the same nesting places, for both eggs and 

 dead young birds of previous seasons were numerous in the tenanted holes containing 

 the fresh eggs. This fact indicates that a very serious waste of life takes place in 

 some seasons, if not annually. It may be accounted for by the late arrival of the bird 

 at its breeding station, which, coupled with the lengthened period of incubation 

 characteristic of all Petrels, results in winter setting in ere the eggs are hatched, or the 

 young, which develop slowly, are old enough to leave the nesting-holes. Another, and 

 perhaps more probable, explanation is that the disasters noticed were due to a succession 

 of cold summers, which are actually known to have occurred. None of the eggs in 

 the summer of 1903-1904 had been hatched when the expedition left the islands on 

 21st February. We may therefore infer that the South Orkneys lie at the extreme 

 limits of breeding for Wilson's Petrel ; indeed, for many individuals of this species 

 — perhaps all — during some seasons the climatic conditions place the islands 

 distinctly beyond that range, though it breeds further south, with similarly 

 disastrous results." 



Eggs of Wilson's Storm-Petrel in the British Museum are of an elongated oval 

 form. They are dull white, peppered with tiny dots of reddish brown and underlying 

 lilac, mostly accumulated round one end of the egg, but occasionally sprinkled all over 

 the surface. Axis, 1.3 inch ; diam., 0.9. 



Adult male. General colour sooty-brown, with a tinge of leaden-grey ; the 

 scapulars and lesser wing-coverts like the back, the median and greater coverts rather 

 lighter and of an ashy-brown, forming a slightly pronounced wing-patch ; primary- 

 coverts and quills black, the innermost secondaries brown like the wing-coverts ; upper 

 tail-coverts white ; tail-feathers black; head and neck, as well as the throat, sooty-brown, 

 with a distinct shade of leaden-grey ; remainder of under-surface sooty-brown, a little 

 lighter than the back ; on each side of the vent a patch of white feathers on the lower 



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