98 LLOYD'S NATURAL HISTORY. 



Adult in Winter Plumage. Mr. Saunders describes this phase of 

 plumage as being similar to that of S. pomatorhinus, the winter 

 dress resembling that of summer, but having a tendency to 

 show striations upon the under parts, and especially on the 

 flanks, while the yellow on the neck is less pronounced. 



Dark Form. On the melanistic birds of the present species 

 Mr. Saunders gives the following note: "The dark-breasted 

 form is rare to the northwards of lat. 70, beyond which the 

 white-breasted one is the representative form ; but southward, 

 both races are found. The colour has no relation to sex, 

 and dark and light birds are constantly to be found paired. 

 The offspring of this union, when adult, is intermediate in 

 character, having a dusky-whitish throat, more or less of an 

 ash-brown band across the breast, and a considerable amount 

 of brown on the flanks. Individuals irregularly spotted with 

 white are not very rare." 



Young. Mr. Saunders describes the offspring of two white- 

 breasted birds as pale cinnamon-brown on the head and under 

 parts, with dark streaks and bars ; the feathers of the upper 

 parts umber-brown, with rufous edges. The offspring of two 

 dark birds is much darker, with greyer tips to the feathers ; 

 while the offspring of one white-breasted bird and one sooty- 

 bird is intermediate, as might be expected. The tarsi and 

 bases of the toes are yellowish, and the front portion of the 

 toes is black. 



Immature birds are streaked and mottled with various 

 shades of brown on the upper surfaces ; mantle chiefly umber; 

 upper tail-coverts barred with dark brown, white, and rufous ; 

 under surface more or less barred with brown on a paler 

 ground (Saunders). 



Nestling. Sooty-brown above, paler on the under surface, 

 the nestlings of dark parents being more dusky than those of 

 the white-breasted ones. 



Characters. The adult of Richardson's Skua is distinguished 

 from that of the Pomatorhine Skua by its smaller size, the 

 wing being less than fourteen inches, and by its long and 

 tapering central tail-feathers, which often project three inches 

 beyond the others. 



