268 BRITISH BIRDS. 



many of the young birds pass southwards in the autumn, and never come 

 back again : many die from the dangers of the journey ; and some probably 

 settle elsewhere. The young of most birds rarely, if ever, remain in the 

 locality of their birth. As soon as they reach maturity and can shift for 

 themselves, the old birds, in a great number of instances, drive them off; 

 whilst with some birds the movement is a voluntary one. Another cause 

 which prevents the increase of our resident birds is the occurrence of hard 

 winters. A long-continued frost or heavy fall of snow causes great mor- 

 tality amongst small birds, of which any one may convince himself 

 by noting the comparative abundance of birds in the beginning and 

 towards the end of winter. The number of resident birds in a spring 

 which follows a hard winter is generally conspicuously below the average. 

 The general colour of the Robin is olive-brown, shading into buffish 

 brown on the flanks and into greyish white on the centre of the belly ; 

 the forehead, lores, ear-coverts, chin, throat, and breast are rich orange- 

 chestnut, the chestnut margined with a few grey feathers on the crown 

 and the sides of the neck. Legs, toes, and claws pale brown ; bill and 

 irides black. The male and female birds are similar in colour. After the 

 autumn moult the colour of the breast &c. is richer. Birds of the year 

 scarcely differ from, adults ; but the young, in nestling-plumage, are 

 spotted, caused by ochraceous centres and nearly black tips to all the 

 smaller feathers of the upper and under parts. 



