THE PERILS OF MIGRATION. 173 



a gale or a storm proves fatal to migrating land 

 birds, many of them frail of form and constitu- 

 tionally weak and feeble. We can therefore readily 

 understand why it is that migrants decline to make 

 any very extended flights across the sea, excejDt the 

 most fleet-winged and robust. On every known 

 sea-route of migration it has been remarked that 

 birds, especially small terrestrial species of compara- 

 tively feeble flight, choose, invariably, the easiest 

 way across, where choice is possible. Some of these 

 sea passages are, of course, wider than others, but 

 every available assistance is made the most use of 

 More than a hundred years ago, a brother of Gilbert 

 White had remarked that the Swallows in passing 

 the Straits of Gibraltar took the narrowest route, 

 flying over the bay in a south-westerly direction, 

 and crossing opposite to Tangier. Ev^en after a 

 long flight is safely accomplished, the resultant 

 fatigue renders the poor little migrants utterly in- 

 capable of escape from the numerous enemies that 

 lurk along the route, or follow like the most re- 

 morseless and bloodthirsty of pirates in their 

 wake. 



The greatest enemies of birds on migration are 

 the various Hawks and Falcons and Owls that are 

 rilways hovering in close proximity to the defenceless 

 moving throng. The large Falcons follow migrating 

 Ducks for enormous distances, preying on the help- 

 less birds at will ; the various smaller Hawks fare 

 right royally on the Warblers, Thrushes, Finches, 

 and such-like Passerine species. Each district 



