OBSERVATIONS ON BIRDS. 303 



SWALLOWS, CONGREGATING AND DISAPPEARANCE 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 uncomfortable 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 ofhirundmee 

 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-martens, above 

 four hundred in number ; but there are other places of 

 rendezvous about the village frequented at the same time. 



naturalist favours the opinion, that part at least of the swallow tribe pass 

 their winter in a torpid state, in the same manner as bats and flies, and 

 revive again on the approach of spring. 



I have frequently taken notice of all these circumstances, which induced 

 Mr White to suppose that some of the hirundines lie torpid during 

 winter. I have seen, so late as November, on a finer day than usual at 

 that season of the year, two or three swallows flying backwards and 

 forwards under a warm hedge, or on the sunny side of some old building ; 

 nay, I once saw, on the 8th of December, two martens flying about very 

 briskly, the weather being mild. I had not seen any considerable number, 

 either of swallows or martens, for a good while 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? 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 



Eassing the winter in a torpid state, but do not absolutely prove the 

 ict ; 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 



MAKKWICK. 



