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The Migration of Birds. By T. A. Coward. Cambridge 

 University Press. Is. net. 



We suppose that there are few studies in Natural Science 

 that lend themselves more to theorizing than the origin, 

 •cause, and paths of those complex movements of birds which 

 we call migration. Mr. Coward (whom we associate with the 

 excellent Fauna of Cheshire) in his preface seems cognizant 

 of this, and does not pretend that this little book is more 

 than a " manual," giving an outline of some of the chief 

 theories culled from various sources, with some elaborations 

 and interpretations of his own ; therefore it is with no surprise 

 that we find in it little or nothing that is new, and that once 

 more we realize how much at present speculation — good. 

 bad, and indifferent — has to take the place of exact knowledge. 

 The absence of the personal element, the outcome of first- 

 hand observation and knowledge, in the book is, however, 

 in our opinion regrettable, even though the intention of this 

 manual is only to set forth the main features of the subject. 

 We are glad to see that the author realizes the utility of 

 ^studying geographical races in connexion with migration — 

 an inestimable help which many seem slow to recognize. 



The old theory that those birds which go farthest north 

 in summer go farthest south in winter, seems to us to be by 

 no means proved, for though the theory has support in the 

 known habits of some species, such as the Knot, it is not 

 confirmed by our knowledge of the movements of other species, 

 such as the Snow-Bunting, which even in north Greenland 

 is partial!}^ resident, and partially migratory. Chapter II. 

 deals with the cause and origin of migration, and in it we 

 iind various speculations, some plausible, some not, and 

 none capable of proof, as can only be expected in our present 

 state of knowledge. In this section, we find one or two 

 loose statements. Thus on page 21 we are told that " intense 

 love of home during the spread of glacial conditions would 

 tend rather towards extinction than formation of ncAv habits," 

 and two species which are cited as having thus become extinct 

 are the Great Auk and the Labrador Duck, both of which, 

 it is well known, became extinct through human agencj^ and. 

 moreover, the latter bird was a migrant, and neither ranged 

 very far north. A little further on Ave read that we may 

 •conclude that the habits of our summer birds in their winter 



