2o8 A WEAKENED IMPULSE 



eggs again when the corn was hoed. And for three 

 years they persisted in trying to breed on that one 

 spot, which was their own home. 



All over the country it was the same: thousands 

 of miles of unenclosed grazing lands were all parcelled 

 out among these birds, each pair in possession of its 

 own well-defined territory. Yet even this bird, so 

 bound to its own place the spot of earth it claims 

 as its very own and holds against all intruders 

 even this species is not unmoved by the migratory 

 impulse, nor wholly without a migration. Towards 

 the end of summer a few are to be seen every day, 

 at all hours, flying steadily due north at a consider- 

 able height; and it is plain to see that these are 

 migrating. And as with the spur-wing lapwing on 

 the pampas, so it is with hundreds of species all the 

 world over resident species and races of which 

 many individuals migrate. And no doubt the reason 

 of it is that the impulse which drives birds to migrate 

 weakens in races inhabiting districts where the con- 

 ditions are favourable all the year round; that the 

 weakened impulse is not strong enough to overcome 

 the attachment to place the intense reluctance of 

 the bird to abandon its home; that the impulse 

 is stronger in the young, and that in species in 

 which the young are persecuted and driven from 

 place to place, first by their parents then by 

 other adults, jealous of intruders, as it happens 

 with this lapwing and with our red-breast and 

 numerous other species, the impulse is unrestrained 

 and eventually sets them off. 



