2 CO Recent Literature. [f^ 



scripts of music sung by Blackbirds, Thrushes, and Skylarks,' and a bibli- 

 ography. 



The 'evolution of bird-song' is a subject that easily lends itself to spec- 

 ulation ; while there is ample basis of fact for the discussion of many 

 phases of the subject, in some respects the field is open for the free use of 

 the imagination. Our author in the main has held himself in good 

 restraint, but of course many of his suggestions are necessarily founded 

 on conjecture. 



After recounting some of the facts regarding the vocal and other 

 sounds emitted by nearly voiceless animals, such as newts, young frogs, 

 serpents and tortoises, and Darwin's theory that voice originated in the 

 involuntary contraction of muscles, through the excitement of fear or 

 anger, he reaches the conclusion that we may consider " the voice to 

 have been evolved from a toneless puffing, indicative of anger, or from 

 snorts or grunts accidentally caused." 



Alarm-notes are produced by the anticipation of danger, while further 

 development of the voice is due to the influence of combat, developing 

 notes of defiance or triumph. "The first call-notes of birds were prob- 

 ably mere adaptations of alarm-cries " ; the simpler songs of many species 

 were at first mere repetitions of call-notes. Proof of heredity is found in 

 the family resemblances between the notes of allied birds, as the call-notes 

 and songs of thrushes, etc., at points geographically widely separated. 

 "It is probable that, speaking generally, the cries of birds which have 

 limited voices are inherited, and that those of what are commonly called 

 ' singing-birds' are perpetuated through the agency of mimicry" — not 

 only of other birds' notes but of sounds produced by -the elements, as 

 " the moaning of the wind in hollow trees," " the murmurs and gurgles 

 of rippling streams," and the sounds made by insects and quadrupeds. 

 These are, in brief, the principal conclusions presented by the author of 

 ' Evolution of Bird-Song.' 



Mr. Witchell is beyond question a keen observer of birds in life, and 

 has given a large amount of time to the subject he here attempts to 

 elucidate. The book is well written, and abounds in interesting and 

 suggestive facts derived from the close study of birds in their natural 

 haunts. Here and there, however, a speculative remark or suggestion 

 might well have been omitted, as either too far-fetched or superfluous 

 to his subject. The 'bibliography of the subject', is quite too general 

 and incomplete to be satisfactory, and we miss from it a number of 

 titles one would naturally expect to find in such a list. A reference like 

 the following, for example — " Zoologist, The. A monthly publication, 

 London" — is hardly the kind of bibliography one will be likely to com- 

 mend who is in search of special papers relating to the ' Evolution of 

 Bird-song.' He appears to have quite overlooked Mr. Samuel N. Rhoads's 

 paper, entitled ' The Mimetic Origin and Development of Bird Language' 

 (Am. Nat. XXIII, March, 1889, pp. 91-103), where he will find his theories 

 and many of his conclusions anticipated by Mr. Rhoads. — J. A. A. 



