LONG-TAILED SKUA 463 



Intermediate forms, male and female. The white on the 

 throat and breast is marked with light-greyish spots and 

 streaks. 



Immature, male and female. Young birds exhibit the 

 tendency to racial distinction at an early stage, according 

 to several observers. But in both dark and light races the 

 immature birds differ from the adults in having the feathers 

 streaked, barred, or edged with various shades of brown and 

 rufous. The upper tail-coverts are conspicuously barred 

 with dark brown, white, and rufous. 



BEAK. Dark brownish-black. 



FEET. Dark brownish-black. 



IRIDES. Dark brown. 



AVERAGE MEASUREMENTS. 



TOTAL LENGTH 20 in. 



WING 13 



BEAK '. 1'5 ,, 



TAESO-METATABSUS 1'25 



EGG ... 2-4x1-6 in. 



LONG-TAILED SKUA. Stercorarius parasiticus (Linnaeus). 



Coloured Figures. Gould, 'Birds of Great Britain,' vol. v, pi. 

 81 ; Dresser, ' Birds of Europe,' vol. viii, pi. 612, fig. 1 ; 

 Lilford,' Coloured Figures,' vol. vi, pi. 35; Booth, ' Bough 

 Notes,' vol. iii, pi. 47. 



This bird, also known as Buffon's Skua, may be dis- 

 tinguished when in adult plumage from other British 

 Skuas by its relatively longer and more pointed central 

 tail-feathers. In other respects it bears a resemblance 

 to the two preceding species, and immature examples 

 of all three, with their short, central tail-feathers, might 

 easily be confounded on the wing. The Long-tailed Skua 

 is, however, the smallest, and the most slender and elegant. 



On British waters this bird is of less frequent occurrence 

 than either of the two last species, but, like them, it is 

 usually seen in September and October, and again in spring, 

 when passing northward to breed. It is most often met 



