xiv MIGRATION 351 



the Swallows will collect together and suddenly vanish, 

 leaving behind them one or two of their number, who 

 may or may not find their way to the far south where 

 their winter should be passed. Even the caged bird, if 

 a migrant, catches the fever and frets impatiently in 

 his prison. It is said that a Brent Goose confined in 

 a yard and longing for his arctic haunts, has been 

 known in spring to migrate from the southern to the 

 northern side of his narrow confines. Winter brings 

 with it the Snipe, the Woodcock, the Fieldfare, 

 Redwing, and many others that come from the north 

 to spend the cold season in our comparatively genial 

 clime. All this is evidence, if we only think of it, of 

 the most marvellous facts. That a Chiffchaff, whose 

 daily occupation for months has been to pick grubs 

 from the trees, and who has never left his favourite 

 wood, should suddenly, some evening, be seized with 

 an uncontrollable impulse to start for North Africa, is 

 surely matter for wonder. Still more astounding is it 

 that the young birds, with defective strength and no 

 experience, should start on the great pilgrimage 

 alone instead of waiting for the old birds to guide 

 them. And in spring, too, when you see the first 

 swallow, it is a startling thought that the small bird 

 whom you see practising his short swallow-flights, per- 

 haps only some ten days before, started on his north- 

 ward voyage from Natal. 



It is one and the same migration of which we 

 catch a glimpse when we see these visitors to our 

 shores, whether it be summer or winter. All alike 

 travel northward in spring and southward in autumn. 

 But the British Isles form part of the northern region 



