LIST OF BIRDS OF PASSAGE. 117 



Virgil, as a familiar occurrence, by way of simile, describes a 

 dove haunting the cavern of a rock in such engaging numbers, 

 that I cannot refrain from quoting the passage : and John Dryden 

 has rendered it so happily in our language, that without further 

 excuse I shall add his translation also. 



" Quails spelunca subit6 commota Columba, 



" Cui domus, et dulces latebroso in pumice nidi, 



" Fertur in arva volans, plausumque exterrita pennis 



" Dat tecto intentem mox aere lapsa quieto, 



" Radit iter liquidum, celeres neque commovet alas." 



" As when a dove her rocky hold forsakes, 



" Rous'd, in a fright her sounding wings she shakes ; 



" The cavern rings with clattering ; out she flies, 



" And leaves her callow care, and cleaves the skies. 



" At first she flutters ; but at length she springs 



" To smoother flight, and shoots upon her wings." 



LETTER I. To THE HON. DAINES BARRINGTON. 



DEAR SIR, Selborne, June 30, 1769- 



WHEN I was in town last month I partly engaged that I would 

 sometime do myself the honour to write to you on the subject of 

 natural history, and I am the more ready to fulfil my promise, 

 because I see you are a gentleman of great candour, and one 

 that will make allowances ; especially where the writer professes 

 to be an out-door naturalist, one that takes his observations from 

 the subject itself, and not from the writings of others. 



The following is a List of the Summer Birds of Passage which I have discovered in this 

 neigJibourhood, ranged somewhat in the order which they appear.* 



RA1I NOMINA. USUALLY APPEARS ABOUT 



1. Wryneck, Jynx, sive iorquilla : The middle of March : harsh note. ' 



2. Smallest \\i\lo\v-\vrenjiegulus non cristatus : March 23 : chirps till September. 



the nest, but, if suffered to fly loose, are very apt to disappear in the spring, and even to join the 

 wild flocks in winter. Were several of them, however, to be brought up together, in a place im- 

 mediately contiguous to a small fir plantation, I suspect they would show no desire to quit the 

 locality, more particularly if accustomed to be regularly fed. ED. 



* The periods of the arrival of our numerous summer birds of passage depend primarily on 

 the state of the moon (for they all migrate by night), an'}, secondarily, on that of the weather, 

 or rather wind; while the instinctive impulse to migrate would seem to be induced by physiolo- 

 gical"causes, the same which afterwards bring about the desire to associate in pairs. Not that 

 this seasonal impulse is itself to be explained upon any known principle, for young birds reared 

 from the nest evince it as forcibly in confinement as in the wild state ; and there are certain phe- 

 nomena connected with migration, as the annual return of birds (both in summer and winter) to 

 their former haunts, which must for ever baffle the ingenuity of man to account for. We can at 

 the most only assimilate this with the principle that impels a pigeon towards its home, and 

 which, it may be, guides also the footsteps of a somnambulist. Still there are various and diverse 

 agencie* which tend somewhat to modify the operation of the migratorv instinct, by accelerating 



