OBSERYATIONS ON BIEDS. 
283 
before ; from whence, then, could these few birds come, if not from 
some hole or cavern where they had laid themselves up for the winter 1 
Surely it will not be asserted that these birds migrate back again from 
some distant tropical region, merely on the appearance of a fine day or 
two at this late season of the year. Again, very early in the spring, 
and sometimes immediately after very cold severe weather, on its 
growing a little warmer, a few of these birds suddenly make their 
appearance, long before the generality of them are seen. These 
appearances certainly favour the opinion of their passing the winter in 
a torpid state, but do not absolutely prove the fact ; for who ever saw 
them reviving of their own accord from their torpid state, without 
being first brought to the fire, and as it were, forced into life again ; 
soon after which revivification they constantly die. — Markwick. 
SWALLOWS, COITGREGATma A^TD DISAPPEAEA^-CE OF. 
During the severe winds that often prevail late in the spring, it is 
not easy to say how the hirundines subsist ; for they withdraw them- 
selves, and are hardly ever seen, nor do any insects appear for their 
support. That they can retire to rest, and sleep away these uncom- 
fortable periods, as bats do, is a matter rather to be suspected than 
proved ; or do they not rather spend their time in deep and sheltered 
vales near waters, where insects are more likely to be found ] Certain 
it is, that hardly any individuals of this genus have at such times been 
seen for several days together. 
September 13, 1791. The congregating flocks of hirundines on the 
church and tower are very beautiful and amusing ! When they fly off 
together from the roof, on any alarm, they quite swarm in the air. 
But they soon settle in heaps, and preening their feathers, and lifting 
up their wings to admit the sun, seem highly to enjoy the warm 
situation. Thus they spend the heat of the day, preparing for their 
emigration, and, as it were, consulting when and where they are to go. 
The flight about the church seems to consist chiefly of house-martins, 
about 400 in number ; but there are other places of rendezvous about 
the village frequented at the same time. 
It is remarkable that though most of them sit on the battlements 
and roof, yet many hang or cling for some time by their claws against 
the surface of the walls, in a manner not practised by them at any 
other time of their remaining with us. 
The swallows seem to delight more in holding their assemblies on 
trees. 
November 3, 1789. Two swallows were seen this morning at ISTewton 
vicarage-house, hovering and settling on the roofs and out-buildings. 
ISTone have been observed at Selborne since October 11. It is very 
remarkable, that after the hirundines have disappeared for some weeks, 
a few are occasionally seen again ; sometimes, in the first week in 
November and that only for one day. Do they not withdraw and 
slumber in some hiding-place in the interval 1 For we cannot suppose, 
they had emigrated to warmer climes and so returned again for one 
day. Is it not more probable that they are awakened from sleep, and 
