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, 
Brak. Dark brownish-black. 
Freer. Dark brownish-black. 
Ir1pES. Dark brown. 
AVERAGE MEASUREMENTS. 
TOTAL LENGTH ae eo ON aim 
WING BSS ner, iat ea ws) # 
BEAK oi cas acd (es rae 
TARSO-METATARSUS =, aap fDi: 
Hee ies » ro pee ASG im. 
LONG-TAILED SKUA. Stercorarius parasiticus (Linneus). 
Coloured Figures.—Gould, ‘ Birds of Great Britain,’ vol. v, pl. 
81; Dresser, ‘Birds of Europe,’ vol. viii, pl. 612, fig. 1; 
Lilford,‘ Coloured Figures,’ vol. vi, pl. 35; Booth, ‘ Rough 
Notes,’ vol. iii, pl. 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 1s most often met 
