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 J ohn Dry den 
has rendered it so happily in our language, that without further 
excuse I shall add his translation also. 
" Qualis spelunca subit5 commota Columba, 
" Cui domus, et dulces latebroso ift pumice nidi, 
Fertur in arva volans, plausumque exterrita pennis 
" Dat tecto intentem— mox acre 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 springe 
" 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 
neighbourhood, ranged someivhat in the order which they appear."^ 
RAII NOMINA. USUALLY APPEARS ABOUT 
1. Wryneck, Jynx, sive torquilla : The middle of March : harsh note. 
2. Smallest wiWow -wren, Regulus 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), and, 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 
agencies which tend somewhat to modify the operation of the migratorv instinct, by accelerating 
