226 NATURAL HISTORY 



get the best fare they can within a certain district, 

 having no inducement to go in quest of fresh turned 

 earth." Now, if you mean that the business of con- 

 gregating is quite at an end from the conclusion of 

 wheat sowing to the season of barley and oats, it is 

 not the case with us; for larks and chaffinches, and 

 particularly linnets, flock and congregate as much in 

 the very dead of winter as when the husbandman is 

 busy with his ploughs and harrows. 



autumn, but of which all return in their perfect plumage. It seems, 

 therefore, that the periodical dispersion of migratory birds towards the 

 north is not occasioned merely by a failure of food, but by some inapti- 

 tude of the climate in which they spend our winter months, to the pro- 

 pagation of their kind. If they were induced to migrate only on account 

 of the inconvenience of the heavy tropical rains, and the failure of winged 

 insects, which are probably beaten down and destroyed by their violence, 

 I conceive no reason why they should not breed in the half of the year 

 which is favourable to their existence in the southern latitudes. I suspect 

 the solution of the point in question to be this : their residence in our 

 winter months is near the equator, where the days are comparatively 

 short and the nights long ; even in our longest days, the redstart, who 

 rears six or seven young, and commences feeding them at three o'clock 

 in the morning, and continues her toil till sunset, has difficulty to main- 

 tain itself well and furnish its young with food ; and if the feeding hours 

 were reduced from seventeen to twelve, the little family would not be so 

 easily reared. If I have disposed of the reason usually assigned for the 

 earlier arrival of the males, it remains to suggest another. It is evident 

 that the migratory impulse is instinctive, and not merely the result of 

 example and education, because young birds which have been brought 

 up in confinement show strong symptoms of uneasiness when the time of 

 departure arrives. Upon dissection of the males when they arrive in the 

 spring, an organic excitement and enlargement is perceptible ; and if the 

 effect of that excitement, in its commencement, creates a restless uneasi- 

 ness and an instinctive desire to seek the proper breeding quarters, the 

 same general law of nature which makes the male solicit what the female 

 hesitates to permit, would make the cocks precede in the act of migra- 

 tion, while the hens with more tardy excitement do not immediately 

 follow them. 



I may take this opportunity of making some further remarks on the 

 acquisition of song or peculiar notes by young birds. The nightingale, 

 which far surpasses all other birds in ]the natural modulation and variety 

 of its notes, and cannot be equalled by any in execution, even if they 

 have learned its song, is peculiarly apt in its first year, when confined, to 

 learn the song of any other bird that it hears. Its beautiful song is the 

 result of long attention to the melody of the older birds of its species. 

 The young whin chat, wheatear, and others of the genus Saxicola, which 



