X." THE MIGRATION OF BIRDS. 773 



inherited instinctive sense of direction possessed by birds in general, 

 and the power of passing from one extreme of their range to the 

 other without the assistance of land marks, or, in the case of the young, 

 direct guidance or personal conduct of such old birds who have made 

 the journey before. A little examination, however, will show that 

 his hypothesis cannot be maintained. It is a well-known fact that 

 the young of various species of wader breeding in high latitudes flock 

 together when they have acquired their flight feathers, and, perfectly 

 independent of their parents, migrate to southern lands, and appear 

 late in July or early in August on the East Coast of England at a 

 time when the supply of food is still most abundant in the arctic 

 lands they have left — lands also in the full glory of the latter summer 

 when as yet the sun has hardly dipped below the horizon. 



Birds go north in the spring to reproduce their species. When 

 this is accomplished, the young are cast off and have to shift for 

 themselves, and in all matters relating to food and movement are 

 dependent on their own inherited instincts to find their way to the 

 ancestral winter quarter — old and young, with the same common 

 object, can and do act independently. The old also are not always 

 able to follow the old trail southward, but frequently enough, under 

 unfavourable meteorological conditions, are compelled to make con- 

 siderable deviations from the normal route ; hence it is that the 

 phenomena of migration vary so much from year to year, both as 

 observed on the East Coast of England, and for half a century at Heli- 

 goland. The act of migration in the young bird is not a habit 

 improved and acquired by observation or instruction, or in any sense 

 to be compared to the training of a homing pigeon, a production of 

 artificial selection and most careful education to a special purpose, 

 and, while possessing no doubt, with all birds, an inherited and 

 instinctive sense of direction more or less latent, has never been sub- 

 jected to the struggle for existence and the same necessities as a wild 

 bird. 



The occurrence of young and old of various species together in the 

 great autumn " rushes " is no indication of personal guidance, and 

 the young of the year are quite as capable of reaching their winter 

 quarters as the old, and for anything we can tell the impulse, instinct, 

 or whatever we may choose to call it, is more strongly developed in 

 the young and vigorous. The great majority of birds migrate during 

 the night, and this alone will preclude any guidance of the young by 

 the old, or knowledge gained by experience of leading land-marks along 

 the route. 



Among the waders the earliest arrivals on the East Coast of 

 England are often a few old birds more or less in faded summer 

 plumage. That these cannot have in any manner acted as guides, or 

 voluntarily undertaken the task of personally conducting the young, 

 is obvious from the time of their arrival not conforming within days 

 and weeks with that of the birds of the year. 



