i86 PARENTAL SOLICITUDE 



birds. And here, too, there is a gradation in the dis- 

 play of feeling from this extreme down to the birds 

 that look on when their nests are robbed, or their 

 young taken and destroyed, and make no sign. But 

 if at such times you look at the parent bird closely, 

 you wall see that its agitation is not less powerful and 

 painful than that of the bird that wheels screaming 

 about your head. 



To take a glance at English bird life, I should say 

 that the swift is one of the demonstrative species. 

 In a book of mine, Afoot in England^ I have described 

 the behaviour of a crowd of these birds in a seaside 

 town in Norfolk, belated breeders in August urged 

 by the migratory instinct into a sort of frenzy before 

 they could bring their young off. 



In another book — Adventures among Birds — I des- 

 cribed the efforts, painful to witness, of a pair of 

 house-martins in October, in cold rainy weather, 

 to induce their full-grown young to come out and fly 

 away with them, and how as soon as the last of the 

 young had perished from cold and insufficient nourish- 

 ment in the nest, the released parents vanished from 

 the scene. 



Again, we are familiar with the fact that caged 

 migrants are stirred by this impulse to fly away, in 

 some instances so powerfully that they injure and 

 even kill themselves in their efforts to escape from 

 their prison. 



One of the most extraordinary instances of this 

 inherited impulse to fly — to escape, as it were, from 

 some imminent danger — of the captive migrant is 



