170 MY NATURE NOTEBOOK. 



birds be brought within range of the remembered 

 landmarks of home. But the natural reluctance of 

 the birds to cross the sea causes them to stick to the 

 coast-lines so long as they can without flying actually 

 against the wind, while the configuration of the land 

 makes them concentrate at projecting headlands, and 

 cross thence to the nearest island or headland of the 

 opposite coast, viewing it at an immense distance 

 from a great height. 



THE ORDER OF TRAVEL. 



Thus the birds seem to follow recognized routes 

 between their summer homes and their winter 

 quarters, although they are simply wandering off 

 when a cold wind blows in autumn or a warm one in 

 spring. In stereotyping this instinct in the birds' 

 minds, Nature has, of course, improved it by small 

 degrees. Of those birds which originally flew with 

 the cold wind only when actual hunger compelled, 

 many must have died by the way ; and those which 

 started first had the best chance of survival. Thus, 

 it is not necessary now to suppose that birds wait 

 until the last minute of safety before leaving their 

 homes. On the contrary, they have acquired the 

 habit of escaping almost at the first suggestion of 

 coming winter in the air, the young birds of the year 

 going off in many cases before their parents have 

 finished rearing their later broods. The old cuckoos, 

 on the other hand, having no nursery duties to detain 

 them, make their own escape before their young are 

 strong enough to migrate. 



