t 



1 92 1. BuRKiTT. — Song and Nesting of Birds. 5 



disappointments. Besides, one observer may have very 

 poor chances and much labour over a species not common 

 in his neighbourhood, which another can study from his 

 hall-door. The process requires for each species that the 

 observer should note a number of separate male birds, 

 preferably from the very beginning of their season ; note 

 their song, if any, and then watch whether any individuals 

 stick sufficiently to one site or are sufficiently isolated 

 from others, or in some other way have their individuality 

 identified. Each of such birds has then to be watched to 

 see if he gets a mate, and the relation of his song thereto, 

 and throughout the subsequent family life. But will the 

 pair remain at the site ? Will you find the nest ? Will 

 the nest be deserted ? Will a parent or the nest be destroyed ? 

 After these risks will you have enough cases left to judge 

 by ? In my experience the odds are that when you have 

 got as far as the nests, at least half of them and probably 

 two-thirds will come to a bad end. Rats, hawks, cats, and 

 boys are I suppose the cause of most tragedies, but some 

 evil spirit will lead a farmer to cut the only clump of weeds 

 or bit of hedge you want left, or lead a miles-man to clear 

 the brushwood off your special bit of railway bank, or the 

 turf-cutter to select your special spot on the moor. I find 

 such a large proportion of my ground-built (or near ground) 

 nests destroyed that I imagine my footsteps must be 

 followed up by rats at night ; or can there be general 

 destruction on such a scale ? Again, desertion is sometimes 

 mysterious, as for example in two cases this year where a 

 pair of Yellow-hammers and another of Garden W^arblers 

 deserted the first nest with eggs, and quickly made new 

 ones within four or five yards. The first nests had not 

 been fingered nor the birds disturbed by me. 



My observations for this article more particularly refer 

 to the Chafhnch, Yellow-hammer, Chiffchaff, Willow Wren, 

 Lesser Redpoll, Sedge Warbler, Grasshopper Warbler, and 

 Greater Whitethroat. 



Probably no hard-and-fast rule binds all the males of 

 a species in their singing, and indeed anything I lay down 

 herein is only meant to be tentative. I wish this to be 

 understood without repeating it. 



