V °^ 3 X ] Recent Literature. J I 



subject in hand, mixed with many assumptions which the general reader 

 would hardly be able to distinguish from the really sound data. Here and 

 there, however, are lapses that betray the amateur rather than the scien- 

 tific investigator, as where at page 69 he speaks of young birds as being 

 "in the normal course of things the first to be in position to migrate; they 

 travel in their first plumage, and consequently are ready to go as soon as 

 they can fly." While this may be true of a few water birds, it is notori- 

 ously untrue of the Passeres and the great majority of land birds. Again 

 (p. 66) Swallows and Shrikes are mentioned as birds "in which the 

 plumage is renewed in early spring," in contrast with others in which the 

 "change is undergone in autumn." We fear Mr. Dixon's field experience, 

 at least as a collector, has been limited, evidence of which is unfortunately 

 not lacking in various parts of the work. 



The book consists of twelve chapters, having the following headings : 

 'Ancient and Modern Views of Migration'; 'Glacial Epochs and Warm 

 Polar Climates' ; 'The Philosophy of Migration'; 'Routes of Migration'; 

 'Emigration and Evolution'; 'Internal Migrations and Local Movements'; 

 'Nomadic Migration'; 'The Perils of Migration' ; 'The Destinations of the 

 Migrants'; 'The Spring Migration of Birds'; 'The Autumn Migration of 

 Birds'; 'Migration in the British Islands.' These titles serve to give a 

 general idea of the character of the book. 



In the first chapter some fifteen pages are devoted to a discussion of the 

 theory of hibernation, the author reciting the well-worn evidence and 

 familiar arguments in its favor, the former dating from the seventeenth 

 century onward; he adduces nothing new on the subject. "Hiberna- 

 tion," he says, "so far as we can learn, only applies to a few individuals, 

 and no species of bird has yet been discovered in which the practice is 

 universal, if we except conditionally the [American] Swift (C. fiela- 

 gica), to which allusion has already been made. As for myself, I neither 

 accept nor deny it, having personally seen nothing to refute or confirm 

 it, although fully believing it possible," etc. 



Mr. Dixon generalizes with great freedom respecting all of the more 

 prominent features of the general subject of migration, often thereby dis- 

 closing an ignorance of the facts in the case naturally to be expected in 

 one who has a ready explanation for nearly every problem. Thus at page 

 24, after instancing the various degrees of migration exhibited in different 

 species, he says : "From the above facts, we may propound the law that 

 wherever the breeding area of a species intergrades with its winter range, 

 migration among individuals breeding in the infringing districts has been 

 suffered to lapse." In this country the contrary is well known ; while this 

 'infringing district' may be permanently occupied by the species, it is 

 evident that it is not occupied the whole year by the same birds; the 

 summer representatives moving more or less to the southward in winter 

 and their places being taken at that season by birds of the same species 

 which have passed the breeding season further north. 



Respecting the cause of migration we have the following: "Birds 

 migrate from necessity, not from choice ; .... I do not know of any 



