A CITY OF BIRDS 57 



so securely guarded on the land-side from prowling 

 fox, weasel or cat by the interlacing branches of the thorn 

 that both herself and her charge were safer where they 

 were. Here is a relevant passage of Mr. Hudson's : — 



" The instinct which in character comes nearest to that of the 

 parent simulating the action of a wounded and terrified bird 

 struggling to escape in order to safeguard its young, is that one, 

 strong in a ground-feeding species, of sitting close on the nest in 

 the presence of danger. Here, too, the instinct is of prime im- 

 portance to the species, since the bird by quitting the nest reveals 

 its existence to the nest-seeking enemy. . . . By leaving its nest 

 a minute or half a minute too soon the bird sacrifices the eggs or 

 young ; by staying a moment too long it is in imminent danger 

 of being destroyed itself. How often the bird stays too long on 

 the nest is seen in the corncrake, a species continually decreasing 

 in this country owing to the destruction caused by the mowing 

 machine. The parent birds that escape may breed again in a safer 

 place, but in many cases the bird clings too long to its nest and 

 is decapitated or fatally injured by the cutters. Larks, too, 

 often perish in the same way." 



But here it was the other way round, for I must assume 

 that the blackbird, for all her fear, was aware of her 

 security. Otherwise, why did she break her habit ? For 

 the instinct to fly the blackbird had rightly substituted 

 the intelligence to take advantage of special circumstance, 

 and stay where she was. Her instinct here, that is to 

 say, would have played her false, where in other circum- 

 stances it would have preserved her. Devotion and policy 

 were here at one, and the incident or lack of it was a 

 striking example of a bird's power of breaking responsively 

 away from fixed instincts on the one hand, and of the 

 marked individual differences in character among birds 

 of the same species on the other. This, too, from the 

 more routine-bound female. For birds to most people 

 are what the Restoration plays are to me — I cannot for 

 the life of me remember one plot from another. 



But if there are examples of intelligent departures 

 from instinct in the domestic behaviour of birds, there 

 are others of stupidity. In an unkempt hawthorn hedge, 

 throwing out long shoots into the adjoining pasture, 

 I found a chaffinch's nest with three eggs in it — ^flesh- 

 coloured in ground colour with a faint bluish tinge and 



