NOV 1^ la-a 



October, 192 1. The Irish Naturalist, 113 



THE RELATION OF SONG TO NESTING IN BIRDS. 



BY J. P. BURKITT. 



This paper is a study in continuation of my article in the 

 January issue of this magazine.^ To observe accurately 

 is hard, to deduce correctly is harder. But the result of 

 about a thousand notes during the past year, combined 

 with previous records ought to be of help in this subject. 



Since the pubHcation of Territory in Bird Life " by 

 Mr. H. E. Howard any new studies and ideas on the 

 rationale of bird habits will, I conceive, be, for a long time 

 to come, compared with the theories and data in that 

 book. Abstracting my notes has been such a considerable 

 labour that I have not attempted to consider " survival " 

 or other values. 



Chaffinch. — I shall begin with the Chaffinch, our most 

 numerous bird. I dealt with ten nests altogether and more 

 or less with fourteen males in an area around my house. 

 Seven of the nests were from 20 to 50 yards from the next ; 

 one later nest came within 14 yards. But most of the time 

 there was no difficulty whatever in allocating the singer to 

 the territory. One mateless bird had an interesting 

 corroboration in the peculiarity of a double song. The 

 general song of the country was also not omitted from 

 observation. Of the ten nests eight followed a normal 

 course, six of these being laid up between April 20th and 

 26th$ two of them being rather late mating and were not 

 laid up till May 3rd. The others were not normal, being 

 as follows : — One pair after beginning a nest about April 

 20th must have had some disturbance, and the second 

 nest was not laid up till May 6th. Another bird lost his 

 first female (found dead) and was for a long time mateless, 

 and the ultimate nest was not laid up till May i8th. 

 Another pair disappeared after choosing a site for their 

 nest. Three other males apparently remained mateless all 

 through, though one of them at least had a temporary 

 female once or twice. 



1 Irish Nat., vol. xxx., 1921, pp. i-io. 



A 



