442 



BRITISH BIRDS. 



they be, are exceptional in a bird -which breeds in an absolutely dark hole. 

 Both facts suggest the idea that the Stormy Petrel has changed its habits 

 comparatively recently. Why it should have changed them, or under 

 what extraordinary circumstances, it would be vain to conjecture. 



The Stormy Petrel is about the size of a Sparrow. There is no difference 

 in the colour of the sexes in this species. After the autumn moult the 

 adult has the general colour of the upper parts slaty black, but the outer 

 web of the greater wing-coverts and the innermost secondaries are narrowly 

 margined with white ; the sides of the rump and the upper tail-coverts are 

 white, the latter broadly tipped with black ; the general colour of the 

 underparts is sooty brown, but the tips of the axillaries and under wing- 

 coverts are white. Bill, legs, and feet black ; irides hazel. It is not 

 known that immature birds differ from adults in colour, but in summer the 

 slaty black of the upper parts fades into a sooty brown. Young in down 

 are uniform greyish brown. 



