i897- THE PROBLEM OF INSTINCT. 165 



would form one of its most interesting and comparatively easy- 

 enquiries. 



Passing over a very interesting discussion as to the habits of the 

 cuckoo and their probable origin, and one hardly less interesting on 

 the habit of the lapwing and many other birds of simulating injury to 

 distract attention from nest or young, we pass on to the broader and 

 more important subject of migration, which, however, is rather briefly 

 treated. The evidence now accumulated seems to justify Professor 

 Lloyd Morgan's conclusion, that while the migratory impulse is 

 innate, yet, " the element of traditional guidance may be effectual, in 

 the migration stream as a whole, in some way that we have hitherto 

 been unable to observe." The chief obstacle to this view consists in 

 the well known observations of Herr Gatke at Heligoland, that, 

 during the autumn migration, in the case of the great majority of 

 species, the young birds migrate earliest and alone, the adults follow- 

 ing considerably later. But admitting, as everyone must, the accuracy 

 of Herr Gatke's observations, does the conclusion necessarily follow ? 

 He himself assures us that the birds which rest on or pass within 

 sight of Heligoland only form a fraction of the whole of the migrating 

 hordes, most of them travelling by night at great altitudes, and very 

 few passing within sight of the island, and of these few only, perhaps, 

 one in ten thousand stopping to rest. The fact that young birds of 

 many species are the first to visit Heligoland every year without 

 exception, may possibly be explained by the fact that, while the older 

 birds which lead the way travel high and go on without stopping, a 

 large number of the young fly lower, and being either fatigued by the 

 long unaccustomed flight or attracted by the sight of the land, descend 

 to this elevated and fertile islet for rest and food. The late Mr. 

 Seebohm, whose extensive journeys to Siberia and in various parts of 

 Europe for the purpose of collecting and studying birds rendered him 

 an authority on this subject, gives the early migration of young birds 

 on the authority of the Heligoland observers, and does not support it 

 by any observation of his own in the northern regions from which so 

 many of the migrants come. In America, although some writers 

 state that young birds migrate first in autumn, Mr. C. Hart Merriam, 

 of the Department of Agriculture, tells us that this notion is " con- 

 trary to the experience of most leading American Ornithologists and 

 to the information collected by the Committee on Migration of the 

 American Ornithologists Union." ^ But if we reject the conclusion 

 based upon the Heligoland facts as not necessarily following from 

 them, we shall find that there is not much difficulty in forming a 

 theory which accounts for the main phenomena, and the outlines of 

 such a theory have been very well expressed by Mr. Seebohm himself 

 at the end of the chapter on Migration in his " Geographical Distribu- 

 tion of the Charadriidae," in the following passage : — 



1 Report on Bird Migration in the Mississippi Valley, by W. W. Cooke, p. 13, 

 Footnote. 



