BIRDS. 219 
and retirmg subsequently to warmer latitudes ; 
some passing to our shores at the commencement 
of winter, staying till spring, and then again wing- 
ing their way to northern abodes, such as the 
Wigeon ; some performing a migration to us only 
from more northern counties on the approach of 
winter, such as the Black-headed gull; some merely 
passing from the northern to the southern shores of 
the county on the occurrence of severe weather, 
such as the Gannet ; some simply from the recesses 
of Dartmoor or other breeding spots, to the culti- 
vated grounds and shores, such as the Lapwing ; 
some only shifting their positions still more incon- 
siderably,—individuals of each kind occupying 
stations during winter where they were not found 
in summer, as is seen in the Water-hen ; while the 
Robin is said to visit the sea coasts in autumn ; 
some species are known to appear here in summer 
only in certain years according to caprice, or some 
unknown determining impulse, this is witnessed in 
the Crossbill, which comes usually about the end 
of that season, and departs before winter; some 
cross over from the continent on the occurrence of 
particularly warm summers,—the Oriole, Bee-eater, 
Hoopoe, and Roze ouzeé are the birds more especi- 
ally alluded to, though no doubt many others might 
be similarly classed. The more frequent occurrence 
of this kind of migrants in Cornwall than in Devon 
is a Clear indication of the circumstances inducing 
their movement, and of the direction whence they 
come. A great many birds seem to lead a wander- 
ing and uncertain life, though this remark chiefly 
belongs to the brds of prey, and some of the Pies ; 
the Nutcracker is a good instance of continued 
propensity to wander, and the Raven seems to be 
incessantly shifting situation at all but the breed- 
ing season. Unusually severe winters, like very fine 
summers, produce great effects on our ornithological 
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