ON THE OCCASIONAL 
DESERTION OF THEIR PROGENY BY BIRDS 
OF THE SWALLOW TRIBE. 
gs 
Tue late celebrated Dr. Jenner, in a posthumous 
“Essay on the Migration of Birds,” published in the 
first part of the ‘Transactions of the Royal Society’ 
for 1824, has briefly adverted to an extraordinary 
occurrence in the domestic economy of two species of 
British Hirundines, which, though far from uncom- 
mon, 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 deser- 
tion of their last-hatched broods by the Swallow and 
House-Martin. ‘This singular fact, with which I was 
familiar previously to its enunciation by Dr. Jenner, 
my own researches confirm and illustrate; I shall 
therefore, without further prelude, proceed to state 
the results obtained from them. 
The Swallow appears in the neighbourhood of 
Manchester on the 15th of April, and the House- 
Martin on the 25th of the same month, at a mean of 
