93 
Even should Gmelin’s account of the rail, Bing- 
ley’s of the owls, and many accounts of hirundines 
prove to be erroneous, it is certain that a part of the 
class, in most countries where hybernation exists, 
feel, about the time when insects and tortoises, &c. 
seek their hybernacula, the impulse of an instinct 
scarce less powerful, and apparently analogous, which 
urges them to remove from a cold to a warmer cli- 
mate. Some, however, of every class appear to ac- 
knowledge this instinctive impulse, and those the 
most, amongst which the evidence of hybernation is 
least traceable *. 
Quadrupeds are less adapted for a rapid passage 
from climate to climate, and therefore many natives 
of cold, and some of temperate regions, appear to 
pass the winter in a state either of long protracted 
sleep, or a deeper state of torpor. With us the 
badger retires to his den, the squirrel to his cham- 
bered store and nest, the dormouse to his warm ca- 
vity. But the dormouse is torpid; the bat, and 
® Noctuas sexagenis diebus hiemis cubare tradit Nigidius.” 
Pliny, Nat. Hist. lib. x. c. 17. 
In Sisson’s Manuel dOrnithologie, Paris, 1828, I find, 
** D’autres (oiseaux) paroissent éprouver une véritable hiberna- 
tion, et ce fait, nié par les uns, affirmé par d’autres, est encore 
dans Pobscurité.” p. 11. 
One kind of hybernation affects birds in a particular by which 
they are eminently and most agreeably distinguished from all 
other classes of animals, namely the voice. Thompson thus 
notices the winter silence of the grove :— 
‘** How dead the vegetable kingdom lies! 
How dumb the tuneful !—” 
