BIRDS. 
219 
and retiring 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-lien; 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 ouzel 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 birds 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 
