406 Recent Literature. [f^^^ 



examples from the structure of various parts of the bird in every discussion 

 of adaptation and development and these chapters impress us as the strong- 

 est. His treatment of geographic distribution is hardly up to date but it 

 is difficult to treat this matter adequately in the short space allotted to it, 

 and the same may be said of the chapter devoted to migration. All in all 

 however, there is little to which exception can be taken in the plan and exe- 

 cution of the ' History of Birds.' It should be in every hbrary and it 

 cannot fail to broaden the views of the younger ornithologists and lead them 

 into lines of research which will yield valuable results in the near future. — 

 W. S. 



Headley's ' The Flight of Birds.'' — The serious study of bird flight 

 brings ornithology into the domain of physics and mathematics and since 

 the average ornithologist does not care to go very far into this field of re- 

 search a book like the present will find a very general welcome, attempting 

 as it does to explain the subject with as few technicalities as possible. 

 Mr. Headley considers flight under several heads: Gliding, Stability, Mo- 

 tive Power, Starting, Steering, Stopping, The Machinery of Flight, Varie- 

 ties of Wing and of Flight, Pace, Wind and Flight, Some Accessories. 

 Numerous excellent illustrations are taken from photographs of flying 

 birds in various positions and under varied conditions. 



In considering the sailing of Gulls against the wind, so often observed 

 from a steamer's deck, Mr. Headley states definitely that the birds are 

 poised on a steady upcurrent of air over the stern of the vessel, caused by 

 the wind striking the sides of the vessel at an acute angle. Mr. William 

 Brewster after careful consideration of this theory dismissed it absolutely 

 after finding that the Gulls sailed equally well, in advance of the vessel, 

 a hundred yards behind, or fifty yards to windward (cf . ' The Auk,' 1912, 

 p. 90). Therefore it would seem that the last word on this problem is yet 

 to be said and it might be profitable as has been suggested to compare the 

 Gulls to the sailing of an ice yacht which, paradoxical as it may appear, goes 

 faster the nearer it is brought into the ' teeth of the wind.' 



Mr. Headley's book is a welcome contribution to an interesting subject, 

 the more so since with the aid of gliders and aeroplanes man is beginning to 

 face the same problems which the bird has solved so successfully. — W. S. 



Howard's British Warblers. Part VI.- — The latest installment of this 

 beautiful work consists of colored plates of the Willow, Savi's, Rufous and 

 Icterine Warblers with text relating to all but the last, while four photo- 



» The I Flight of Birds j By P. W. Headley, M. B. O. U. | Author of "The Struc- 

 ture and Life of Birds" ! "Life and Evolution" &c 1 With Sixteen Plates | and 

 Many Text Figures | Witherby & Co. | 326 High Holborn | London | 1912. — 

 Crown 8vo., pp. i-x + 1-163, with 16 plates and 27 text figures. Price 5s. net. 



2 The I British Warblers | A History with Problems | of 1 their Lives | by 

 H. Ehot Howard, F. Z. S., M. B. O. U. | Illustrated by Henrik Gronvold | London 

 R. H. Porter i 7, Princes Street, Cavendish Square, W. | Price 21s. net. — Part 6. 

 December, 1911. 



