Introduction 13 
modifications, as is done by the blackcap ? Tbis imitation is 
even said by one writer (YH, vol. 1 , p. 420, ed. 4), to detract 
fiom the excellence of the bird’s natural song’. The imitation 
of other sounds by the starling is constantly referred to by 
ornithological writers. The sedge-warbler is said to imitate 
the notes of other birds, particularly those of the sparrow, 
swallow, and skylark, and has often been called the English 
mocking-bii d. It executes its imitations in rather a hurried 
but very pleasing manner” (BH, vol. 2, p. 69). True mocking¬ 
birds show the extreme to which imitation may be carried; but 
if imitation detract from the Quality of the song, would that 
not be a fatal disadvantage were the song purely sexual? A 
cm tain amount of imitation is, no doubt, common enough, and 
Y itchell (WE, pp. 165 et seq .) quotes many writers to this 
effect, the mimicking birds being the redstart, blackcap, sedge- 
warbler, marsh-warbler, reed-warbler, white-throat, skylark, 
whmehat, stonechat, wheat-ear, greenfinch, etc., and Witchell 
himself (WE, pp. 195 et seq., and 201 et seq.) produces tables 
showing various bird-notes imitated by thrush, robin, skylark, 
starling, sedge-warbler, the different kinds of birds imitated by 
these five, numbering respectively thirty, twenty-two, fifteen, 
sixteen, and eleven. He also records the imitation of the 
barking of a dog by a starling, and even the bleating of a 
sheep by a skylark. At first one is inclined to agree with him; 
until as he accumulates evidence one grows doubtful, and 
finally sceptical. He goes too far. 
the whole question of imitation, or mimicry, is, however, 
debatable. Certain notes and combinations of notes may be 
common to many species; certain ones are without doubt 
common to several, and many apparent imitations may in 
reality be natural notes; and of many it may be difficult to say 
which bird is the imitator, which the imitated. 
No doubt imitation plays an important part in the education 
of the young bird, though it has not been shown why a young 
bird will imitate the song of its own species rather than that 
of another. Written evidence is again wildly confused. 
Romanes (RM, pp. 222-3) quotes Couch to show that “singing 1 
to to 
