DESERTION OF YOUNG. 383 



lodge the young proving ineffectual, they entirely 

 closed up the aperture with clay, so as to convert 

 the nest into a sepulchre for their dead progeny. 

 At first, Mr. Blackwall was disposed to attribute 

 the untimely fate of the nestlings, thus unexpect- 

 edly discovered, to the accidental destruction of 

 one or both parents; but a little reflection induced 

 him to change his opinion. So many instances 

 were called to mind of the sudden departure of 

 house-martins at periods when, to all appearance, 

 they were most busily engaged in providing for 

 their families, that what was before regarded 

 as the unavoidable consequence of an accidental 

 circumstance, was now considered possibly to have 

 been occasioned by a voluntary act of desertion. 

 To clear up this doubtful point, several examina- 

 tions were made, at the second of which, on the 

 22d of October, several nests, both of swallows 

 and of martins, were found to contain dead young 

 ones. At a third search, on the 19th of Novem- 

 her, fourteen nests were examined; four of them 

 contained dead nestlings, 1 and one nest contained 

 two eggs, whose contents very plainly showed 

 that they had been forsaken when on the point of 

 being hatched. A fourth search was made, on 



