HYBERNATION OF BIRDS. 120 



time as much atmospheric air as a porpoise.* 

 The winter sleep of the swallow in question 

 (Hirundo riparia) is not supposed to belong to 

 the entire species, but only to have been ob- 

 served in some individuals."f 



Gilbert White, who, with others of his day, 

 firmly believed in the submerged winter state 

 of the swallow tribe generally, in one passage 

 expresses his suspicions that the sand martin, 

 which often makes its appearance at the begin- 

 ning of April, does not leave its wild haunts at 

 all, but that the flocks are secreted amidst the 

 clefts and caverns of those abrupt cliffs where 

 they usually spend their summers. But he just 

 previously states, that on a diligent examination 

 of their breeding-holes in sand banks nothing 

 but the old nests were found. 



Dismissing the submergence theory as utterly 

 untenable, let us pass to another view of the 

 question — Do swallows or any other birds hyber- 

 nate, either regularly or accidentally, in holes 

 or crevices, like bats ? Markwiek says, " I 

 have frequently taken notice of all those circum- 

 stances 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 is 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 martins 



* Lavoisier Mem, de CJihme. 

 f Milne Edwards' Elimens de Zoologie, 1834. 

 E 



