ON A 



REMARKABLE FACT 



IM THB 



NATURAL HISTORY OF THE SWALLOW 

 TRIBE. 



BY JOHN BLACKWALL, F.L.S. 



(Read March 23rd, 1826.) 



A HE late celebrated Dr. Jenner, in a posthu- 

 mous essay on the Migration of Bu-ds, published 

 in the first part of the Transactions of the Royal 

 Society for 1824, has briefly adverted to an 

 extraordinary occurrence in the domestic econo- 

 my of two species of British hirundines; which, 

 though far from uncommon, has either been 

 altogether overlooked, or totally disregarded, by 

 every preceding writer on ornithology whose 

 works I have had an opportunity of consulting. 

 The circumstance alluded to is, the occasional 

 desertion of their last hatched broods by the 

 swallow and house-martin. This singular fact, 

 with which I was familiar previously to its an- 

 nunciation by Dr. Jenner, my own researches 

 confirm and illustrate ; I shall, therefore, without 

 further prelude, proceed to state the results ob- 

 tained from them. 



