286 BRITISH SEA BIRDS. 
of certain Arctic-nesting species, frequenting the 
British coasts throughout that season. The 
presence in our area of these northern birds 
during summer, has not unnaturally led to the 
supposition that they actually breed there. In 
autumn the order of migration is, to some extent, 
reversed. At that season a few old birds of either 
sex are the first to arrive, sometimes preceding, and 
always invariably accompanying, the flights of 
young birds, which are then moving south. Many 
of these young birds start off from their birth-place 
almost as soon as their wings are strong enough to 
bear them, and individuals of certain Arctic species 
have been met with on our coasts with particles of 
the down of their nestling plumage still adhering to 
their feathers. The adult males come south next; 
the females following; and last of all come the 
cripples and the weakly—the individuals that have 
been retarded in their flight by accidents of various 
kinds, such as the loss of wing feathers, by deformi- 
ties, or by disease. The observer on the coast will 
also remark considerable diversity in the social or 
gregarious tendencies of these migrants. Some 
migrate gregariously in numbers that are as un- 
countable as the pebbles on the shore; others 
journey in family parties, in small flocks, or even 
singly. The migration of each species is usually 
first remarked by the appearance of an odd bird 
or two; then the numbers increase, perhaps with 
two or more great rushes when the flight of that 
