xxTi THE PROBLEM OF INSTINCT 505 



the young birds have had no practice in long continued 

 flight and no experience of the dangers of the sea. If 

 the birds of more than one season live on the average only 

 four or five years more, it follows that only a very small 

 percentage of the enormous annual progeny of young birds 

 can survive to take their place. Hence it may well be 

 that all those countless myriads of birds of the year that 

 visit Heligoland are among the failures which, if they 

 leave the island, perish in the waters. We know that 

 enormous numbers must perish during each year, and 

 where so likely as during that first attempt to traverse 

 the North Sea ? This is rendered almost certain by the 

 recently issued Report of the British Association Com- 

 mittee on Bird Migration, in which it is stated that at 

 the various periods of the great autumnal rushes at 

 Heligoland, when countless thousands of birds visit or pass 

 over that island, no corresponding influx has been noticed 

 on our east coasts during the four successive years that 

 the two records have been compared. Either then, these 

 myriads of birds passed southward to Holland or flew out 

 to sea and were mostly lost. As Herr Gatke does not 

 mention any corresponding flights along the coasts of 

 Holland and Belgium it is to be presumed that they have 

 not been noticed, and we are almost forced to the con- 

 clusion that the greater part of these young birds, whose 

 immense numbers at Heligoland excite so much astonish- 

 ment, are really failures, and form a portion of those 

 which are annually eliminated by the severe test of mi- 

 gration ; and if this be so, much of the marvel supposed 

 to attach to the successful migration of young birds 

 disappears, since such " successful migration," except in 

 the case of a small percentage, does not occur. 



The alleged Homing Instinct. 



There is one alleged instinct of great popular interest 

 which Mr. Lloyd Morgan does not deal with — the means 

 by which many of our domestic animals, especially cats, 

 dogs, and horses, find their way home under circumstances 

 which seem to preclude any direct guidance by the senses. 



