320 THE NESTS AND EGGS OF BRITISH BIRDS. 



Breeding habits : The Stormy Petrel is a resident 

 in the British seas, subject to much local movement, 

 and only coming to land to breed, or when driven in by 

 stress of weather. Its favourite breeding-haunts are 

 rocky islands which contain a fair amount of uneven 

 turf-clad downs more or less strewn with rock fragments. 

 It is gregarious during the breeding season, numbers of 

 pairs resorting to certain favourite localities to rear 

 their young. It is probable that this little Petrel pairs 

 for life. The slight nest of a few bits of dry grass is 

 made either in an old rabbit-earth or Puffin burrow, 

 under a rock or a heap of loose stones, or even amongst 

 ruined walls and other masonry. In some cases no 

 provision of any kind whatever is made, and the &g^ 

 rests on the bare ground. This Petrel is a remarkably 

 close sitter, so that one could wander about its breed- 

 ing-places without being made aware of the fact. It 

 sits close in its burrow or crevice until dragged out ; at 

 dusk, however, the birds become more lively, and may 

 then be seen flitting about in a ghostly way near their 

 nest-holes, leaving and returning to them. Many nests 

 are often made close together. 



Range of egg colouration and measurement : 

 The Stormy Petrel only lays one &^g each season, but 

 if this chance to be taken it is generally replaced. It 

 is pure white in ground colour, chalky in texture and 

 without gloss, and almost oval in form. From a casual 

 glance many eggs look entirely spotless, but a fine 

 sprinkling of minute red spots, most of them in the form 

 of a zone round the larger end, in somes cases so small 

 as to look like dust, may be detected. Average 

 measurement, i"i inch in length, by "83 inch in breadth. 

 Incubation, performed by both sexes, lasts from thirty- 

 three to thirty-five days. 



Diagnostic characters : The small size, chalky 



