ESSAY V 



ON THE TORPIDITY OF THE SWALLOW TRIBE, 

 WHEN THEY DISAPPEAR. 



IN the foregoing treatife upon the migration of birds, the 

 appearance and difappearance of the fwallow-tribe hath ne- 

 ceffarily been touched upon ; but I think it better to referve, 

 for a feparate dilfertation, what more particularly relates to their 

 being during the winter in a ftate of torpidity. 



I have for many years attended carefully to the motions of thefe 

 birds from the latter end of March to the latter end of April, 

 at which time I have travelled into, or returned from, North 

 Wales. 



For the laft twelve years the fpring feafons in that part of 

 Great Britain have been generally dry, the eaft winds prevailing 

 during the month of April. 



The confequence hath been, that on my journey towards 

 Wales, or upon my arrival in the principality, I have perhaps 

 feen a flraggling fwallow or fwaliows a ; but upon the weather 



growing 



a As ofccn martins. I mall here fubjoin a letter which I received 

 from that ingenious and obiervant naturalifc the Rev. Mr. White, of 

 Selborne in Hampfhire. 



"Dear Sir, Selborne, Nov. 22, 1777, 



You cannot but remember that the 26th and 27th of lafl March were 

 very hot days; fo fultry that every body complained, and were refUefs 



G g under 



