452 THE ZOOLOGIST. 



start its song just as it leaves a tree, and however long its flight 

 may be (it is never of any great length), it maintains throughout 

 it the slower opening phrases of the song, saving up the rapid 

 concluding trill until the moment of its alighting in the second 

 tree. 



The most remarkable instance of a bird's singing on the wing 

 that has come under the writer's notice was one furnished by a 

 Chiffchaff. The bird was chasing another, presumably the 

 female, on the outskirts of a wood ; the two were flying at an 

 incredible speed close to the ground and near a hedgerow, the 

 pursued making sudden turns and twists, which were followed 

 closely and with perfect precision by the pursuer ; and one of 

 them, probably the pursuer, was repeatedly uttering the clear 

 " chip, chop " almost as placidly as though he were singing from 

 his accustomed tree-top. It may be remarked in passing that 

 the powers of flight held in reserve by these smaller Warblers 

 are extraordinary. This fact is occasionally illustrated in a 

 most surprising manner by the Willow-Wren. Just after their 

 arrival in the spring (possibly when only the males are about). 

 Willow- Wrens are exceedingly pugnacious, and one may some- 

 times be seen to take up a position on a post, or in the lower 

 branches of a tree, and from there to make fierce sallies upon 

 any bird not larger than a Finch that happens to be flying by ; 

 it will always take especial pleasure in attacking a Sand-Martin 

 — indeed, the Sand-Martin seems to be a common butt for 

 any small bird's exuberance of spirits ; and in every case the 

 Willow-Wren will exhibit on the wing a command both of speed 

 and agility which is in the greatest possible contrast with what 

 one would expect from the everyday deportment of its life. It 

 is a sight that in a measure prepares one's mind for the startling 

 conclusions reached by Gatke, and makes it a little easier to 

 understand how such small and delicate birds as these can con- 

 duct with so much speed and success their long migrations over- 

 seas. 



The slight revival of song that takes place in the autumn has 

 often been remarked upon. The most conspicuous part in it is 

 taken by the Chaffinch, Yellowhammer, Willow- Wren, and Chiff- 

 chaff; the Lesser Whitethroat also sings a good deal in early 

 autumn, but omits the string of loud notes that form the ending 



