266 CORVIDJE. 



Among British birds there is none able to imitate the 

 varied sounds of the human voice more successfully than 

 the Eaven, and many instances are known of its talking 

 with a distinctness of articulation and accuracy of tone 

 that are almost perfect, while it will occasionally utter 

 phrases that by their accidental aptness are positively 

 startling to the hearer, and produce an effect not to be 

 exaggerated even in fiction. Here there is no need to 

 repeat any of the oft-told stories in proof of its mocking 

 man's speech, but the fact that it can do so leads us to con- 

 sider the means whereby the exercise of that faculty is pos- 

 sible, and this, it will be found, has a direct bearing on some 

 important points in Systematic Ornithology. 



The various powers of voice possessed by birds in general, 

 caused by the diversity of structure of the windpipe, have 

 justly excited the'attention of many of the greatest zoologists, 

 from Cuvier to those of our own day, inducing them to 

 carry on investigations which have finally contributed 

 (among other things) to the establishment of a far sounder 

 mode of classifying the forms combined in preceding 

 Editions of this work in an " Order " to which the name of 

 INSESSORES was applied by Vigors*. Without attempting 

 to recount fully the progress of these researches, or the 

 way in which one investigator after another improved on the 

 method of his predecessor, it will be sufficient and expedient 

 here to state briefly the chief results that have been reached, 

 so far as they affect the members of the British Fauna. It 

 has been long known that each of the Orders Piece and 

 Passeres established by Linnaeus was composed of a very 

 heterogeneous assemblage, artificially grouped together, and 



* This "Order" was propounded in 1823 (Trans. Linn. Soc. xiv. p. 425), 

 and the name published in 1826. It comprehended all the genera included by 

 Linnaeus in his Orders Piece and Passeres, with the exception of Columba and the 

 addition of Lanius. In accordance with the principles of the " Quinary System' 

 based on an hypothesis then and later adopted by many of the best English 

 zoologists, but now finding few or no adherents the new Order was divided 

 into five "tribes " -. Dcntirostres, Conirostres, Scansores, Tenuirostres and 

 Fissirostres, an arrangement followed by the Author of this work. That these 

 ' ' tribes " were unnatural groups will presently appear, and accordingly allusion 

 to them is omitted throughout this Edition. 



