Tum cornix plena pluviam vocat improba voce
Et sola in sicca secum spatiatur arena;[69]
while corvus is gregarious, as is shown in the following memorable description of Nature and of the birds taking heart after the storm has passed:—
Tum liquidas corvi presso ter gutture voces
Aut quater ingeminant, et saepe cubilibus altis,
Nescio qua praeter solitum dulcedine laeti,
Inter se in foliis strepitant; juvat imbribus actis,
Progeniem parvam dulcesque revisere natos.[70]
That in these last beautiful lines corvus means a Rook, no Englishman is likely to deny; yet there are two difficulties to be put aside before we can make the assertion with entire confidence. The first is, that Virgil, here following Aratus, translated by corvus the Greek word κόραξ, which is not generally accepted as meaning a Rook. This is the word which the Greek historian Polybius uses for those naval machines invented by the Romans, in the first war with Carthage, for grappling with a hooked projecting beak the galleys of the enemy; and the rook’s bill is hardly so well suited to give a name to such an engine as that of the crow or raven,[71] which has the tip of the upper mandible sharply bent downwards, like that of most flesh-eating birds. Still I must hold it probable that Aratus here used the word for the rook, as he makes it gregarious, and so, I think, did the Alexandrian scholar Theon, who wrote a commentary on his poem. The only other possibility is that he was thinking of the Alpine Chough, a bird which he might possibly have known, and one of thoroughly social habits. But that Virgil, though he too probably knew this bird, was not thinking of it when he wrote the lines just quoted, I feel tolerably sure; he would most likely have used the word graculus rather than corvus, which would seem never to have been applied, like monedula and graculus, to the smaller birds of the group, such as the Alpine Chough and the Jackdaw.
The second difficulty lies in the fact that the Rook is now only a bird of passage in Italy, never stopping to breed in the southern part of the peninsula, and very rarely in the northern; while Virgil speaks of the corvi in the last-quoted passage as loving to revisit their nests. But this difficulty has been overcome by the delightful discovery that the Rooks still stay and breed in the sub-alpine neighbourhood where Virgil passed his early life.[72] As I have remarked about the pigeons and the stork, the climate may have been such as would induce some birds to stop south of the great Alpine barrier, which now find there no climate cool enough for breeding; and the Rook was perhaps a more regular resident and breeder then than he is now.