522 Letters, Extracts, and Notes. 



Habits of Nestling Birds. 



Sir, — After reading Mr. Swynnerton's account of tlie 

 coloration, etc. of nestling birds, I venture to record 

 the following note on the behaviour of young birds at 

 night. Two or three years ago my attention was drawn 

 to a fact that was contrary to what I had previously 

 supposed — namely, that in the case of young Robins which 

 were more than half-fledged, the old bird did not roost on, 

 nor even near, the nest at night. Moreover, when the nest 

 was touched, the nestlings went through a curious spas- 

 modic action. With their shoulders hunched and quills 

 ruffled, they jerked themselves up and down until the nest 

 shook, meanwhile thrusting their heads to and fro, and 

 making a low snapping sound with their bills which was 

 quite unlike any sound I have heard from them by day. 

 This spasm of movement lasted, roughly speaking, for from 

 ten to twenty seconds, and was most characteristic though 

 rather difficult to describe. It seemed to be quite auto- 

 matic, in response to the stimulus of touching the nest, 

 and the birds' eyes were shut all the time. During that 

 and the following summers I have visited various nests at 

 night, and have always got this behaviour more or less 

 marked in Robins, in which species 1 have never seen the 

 old bird roosting at the nest. In Blackbirds and Thrashes 

 I have never seen it — there the parent frequently roosis 

 with the young. I. saw it again very markedly in the case 

 of a brood of young Nightingales — here the old bird was 

 roosting on a twig beside the nest— and less distinctly in 

 some Chaffinches, where the old bird was not seen. 



Yours truly, 

 Old Hall, M. D. Haviland. 



Newnbam College, 



Cambridge. 

 12 May, 1916. 



Sir, — In connection with Mr. Swynnerton's remarks on 

 " warning coloration '^ and the comparative " edibility " of 

 certain species in the last number of ' The Ibis,' it might 



