4 THE POPULAR SCIENCE MONTHLY. 



some time since flown, he has recommenced singing vociferously 

 at intervals throughout the day; and doubtless, in conformity 

 with what I have observed elsewhere, will go on singing till July. 

 How marked is the direct relation between singing and the con- 

 ditions which cause high spirits, is perhaps best shown by a fact 

 I noted on the 4th December, 1888, when, the day being not only 

 mild but bright, the copses on Holmwood Common, Dorking, were 

 vocal just as on a spring day, with a chorus of birds of various 

 kinds robins, thrushes, chaffinches, linnets, and sundry others 

 of which I did not know the names. Ornithological works fur- 

 nish verifying statements. Wood states that the hedge-sparrow 

 continues " to sing throughout a large portion of the year, and 

 only ceasing during the time of the ordinary molt." The song 

 of the Blackcap, he says, " is hardly suspended throughout the 

 year ; " and of caged birds which sing continuously, save when 

 molting, he names the Grosbeak, the Linnet, the Goldfinch, and 

 the Siskin. 



I think these facts show that the popular idea adopted by 

 Mr. Darwin is untenable. What then is the true interpretation ? 

 Simply that like the whistling and humming of tunes by boys 

 and men, the singing of birds results from overflow of energy 

 an overflow which in both cases ceases under depressing condi- 

 tions. The relation between courtship and singing, so far as it 

 can be shown to hold, is not a relation of cause and effect, but a 

 relation of concomitance : the two are simultaneous results of the 

 same cause. Throughout the animal kingdom at large, the com- 

 mencement of reproduction is associated with an excess of those 

 absorbed materials needful for self -maintenance ; and with a con- 

 sequent ability to devote a part to the maintenance of the species- 

 This constitutional state is one with which there goes a tendency 

 to superfluous expenditure in various forms of action unusual 

 vivacity of every kind, including vocal vivacity. While we thus 

 see why pairing and singing come to be associated, we also see 

 why there is singing at other times when the feeding and weather 

 are favorable ; and why, in some cases, as in those of the thrush 

 and the robin, there is more singing after the breeding season 

 than before or during the breeding season. We are shown, too, why 

 these birds, and especially the thrush, so often sing in the winter : 

 the supply of worms on lawns and in gardens being habitually 

 utilized by both, and thrushes having the further advantage that 

 they are strong enough to break the shells of the hibernating 

 snails : this last ability being connected with the fact that thrushes 

 and blackbirds are the first among the singing birds to build. It 

 remains only to add that the alleged singing of males against one 

 another with the view of charming the females is open to parallel 

 criticisms. How far this competition happens during the pairing 



