68 THE WARBLERS 



prettily beneath the leaves, but usually creeping under, and reaching 

 up to them. All will frequently catch their prey in the air. I have 

 seen a willow-wren break off a song, which he had begun when on 

 the ground, to flit upwards after a fly. All again may be seen 

 hopping in search of food upon the ground, the wood-wren less 

 often than the others, and very rarely when leaf is well out, and 

 food abundant in the tree-tops. 



When the young are discovered, the parents will sometimes feign 

 injury in order to draw the intruder away from the nest. I have 

 seen this more than once done by the willow-warbler ; and it is 

 asserted on the authority of Naumann to be the habit both of the 

 chiffchaff and wood-wren. A detailed description of the actual 

 postures assumed by one bird, a hen willow-warbler, has been given 

 by Mr. Kingsley Siddall. 1 This bird flew on to a wooden paling, 

 and instead of fluttering away as is usual, stood on her right leg, 

 the left hanging behind her. The right wing hung as if broken, 

 the tail-feathers were spread out, and those on the throat and rump 

 puffed out. The head was inclined to one side, the bill slightly 

 opened, and from it there issued "several curious squeaky little 

 calls," which were quite unlike the usual plaintive notes of alarm. 

 As soon as the bird judged the danger over, she flew off* to a tree 

 near by, and uttered the usual call. Detailed descriptions of this 

 kind are of great value, because they make it possible to compare an 

 animal's various modes of expression. In the case of the willow-wren 

 the puffing of the feathers and spreading of the tail no doubt also 

 form part of the love-display, possibly also the squeaking notes. Such 

 comparisons may further prove to throw light on the origin of the 

 feigning instinct itself, and from this to the fundamental unsolved 

 problems of evolution there is but a step. 2 



The young remain in the nest about a fortnight. On one occa- 

 sion I inadvertently startled a nearly fledged brood of willow- warblers 



1 British Birds, iv. p. 119, where a diagrammatic sketch of the posture is also given. 



2 For a detailed discussion of the origin of the feigning instinct, see Lloyd Morgan's Habit 

 and Instinct, p. 248. 



