Vol. IV. 

 1904 



J From Magazines, &c. 



Taverner goes on, by what may be roughly called destructive 

 analysis, to the Darwinian theory that the movement is due to 

 " a natural desire of the individuals to disperse during the breeding 

 season," which opinion he advances some logical arguments 

 against. One fact deserving attention is thus stated : — " On the 

 whole I doubt very much whether the bird population in the 

 breeding season is any less per given unit of territory than at 

 other times." Dr. A. R. Wallace's idea, propounded in " Island 

 Life," that " the migrants are in search of soft-bodied insects 

 suitable for nestlings," is next considered. In answer to this it is 

 contended — " It may be objected that each species requires its 

 own special food at the critical nesting period, which may not be 

 obtainable everywhere. Now, if there is any truth in our present 

 evolutionary theory, great changes in food habits must have 

 occurred in all our species. . . . Food habits could never 

 have originated migrations, though migration has had a great 

 influence in modifying food habits. It must be remembered also 

 that migration is a dangerous undertaking to a race. 

 The one cause that seems adequate is ... . the suf^ciency 

 of the food supply." As to Mr. J. A. Allen's suggestion that 

 " migration is the only manner in which a zoological vacuum in 

 a country whose life-supporting capacity is a regularly fluctuating 

 quantity can be filled by non-hibernating animals," Mr. Taverner 

 considers it correct, but points out that there are arguments 

 against this also. The conclusion arrived at is : — " These migra- 

 tions, in their earlier stages, must have originated in a conscious 

 seeking for food. In course of time the movement became 

 habitual, and generations of repetition rendered it instinctive." 

 This forces us back on the theory of habit — one of those put 

 forward by Captain Hutton and Mr. J. Drummond, in a work 

 noticed elsewhere — and after all hardly solves the problem why 

 such extremely long and rapid flights as are taken by some species 

 during migration — from Siberia to New Zealand, perhaps beyond 

 — should occur, or the virtually entire desertion by certain species 

 of one hemisphere to proceed to another at a definite time ; and 

 hardly answers the question why birds go hence to arctic regions. 

 It would be more applicable to such facts as are recorded in two 

 other papers in the same issue of The Auk on migration, in one 

 of which the effect of altitude is discussed by Mr. Wells W. Cooke, 

 and in the other (" Spring Bird Migrations of 1903 ") it is admitted 

 in the first sentence that " bird migration is a very elusive sub- 

 ject." The author of the latter paper draws attention to the 

 " general relationship between weather and bird waves," but 

 admits that " it is not true that birds travel only with the aid of 

 favouring winds ; nor when the weather gets warm enough to 

 be grateful to their sensibilities." In a subsequent paper (p. 347) 

 Mr. J. A. Allen, one of the editors, has some remarks worth the 

 consideration of our nomenclature committee. The present 

 number also includes the 13th supplement to the " A.O.U. 

 Check-List." 



