THE SKUA GULLS AND THEIR RECENT MIGRATION. 91 
has already supplied him with particulars; but it may not be a 
vain repetition to point out here the distinguishing characteristics 
in the immature examples of both species, which alone can 
present any possible difficulty. The general dimensions of the 
Pomatorhine are considerably larger than in Richardson’s Skua. 
In the smallest immature Pomatorhine the wing (measured 
underneath, and therefore short measurement) is 13°7 in. from 
carpal joint to tip, and the tarsus 2°51in.; whilst in Richardson’s 
these parts are respectively 12in. to 12°5in. and 1°7in.; also 
in the former there is much more white on the inner webs of the 
primaries, and the central rectrices, besides projecting but little, 
have their points of a rounded shape, very different from the 
pointed form assumed by those feathers in a Richardson’s Skua 
of even a few months old. The young of the Pomatorhine are 
usually of a sooty brown, more or less mottled with white on the 
under parts with advancing age, until in very old birds the dark 
pectoral band entirely disappears, and the whole breast and 
abdomen down to the vent (which is dark) becomes white. 
Specimens in such fully adult plumage are, however, rare; and in 
one, obtained in the Faroes in May, 1877, the central rectrices 
are of the unusual length of 3°7in., their rounded and half- 
twisted shape being wholly different from those in any other 
species. 
In its migrations, so far as are recorded, the Pomatorhine 
seems to have been more frequently noticed along the east side 
of Britain, after which it suddenly turns up in tolerable abun- 
dance on our S.W. coast, especially at Torbay; but from these 
scattered facts few deductions of any value can be drawn, for 
observers are few and far between, and it is but rarely that 
these birds come sufficiently close to land to afford opportunities 
for observations. As Mr. Booth pertinently remarks, there is 
probably nothing unusual in the present migration beyond the 
fact that, owing to the winds and weather prevalent at the time, 
the birds have come closer to the coast, and have consequently 
been more remarked. If the fishermen all round our islands 
were practical ornithologists, and in the habit of recording their 
observations, we should in a few years be wonderfully enlightened, 
not only with regard to the migrations, but as to the frequent 
occurrence some thirty or forty miles from shore, of species 
which are often described as “very rare and accidental visitors,” 
