October brings the slender gray wagtail, pied ash colour and white, with a large black velvet gorget. The charming bird, running and wagging its tail, follows the ploughman almost under the horses’ feet, picking up insects in the newly turned furrow. About the same time comes the lark,—first in little companies thrown out as scouts, then in countless bands which take possession of cornfield and fallow, where abounds their usual food, the seeds of the Setaria. Then on the plain, amid the sparkle of dewdrops and frost crystals suspended to each blade of grass, a mirror shoots intermittent flashes under the morning sun. Then the little owl, driven from shelter by the sportsman, makes its short flight, alights, stands upright with sudden starts and rolling of alarmed eyes, and the lark comes with a dipping [[201]]flight, anxious for a close inspection of the bright thing or the odd bird. There it is, some fifteen paces away—its feet hanging, its wings outspread like a saint-esprit. The moment has come; aim and fire. I hope that my readers may experience the emotions of this delightful sport.
With the lark, and often in the same flocks, comes the titlark—the sisi—another word giving the bird’s little call. None rushes more vehemently upon the owl, round and round which it circles and hovers incessantly. This may suffice as a review of the birds which visit us. Most of them make it only a halting-place, staying for a few weeks, attracted by the abundance of food, especially of insects; then, strengthened and plump, off they go. A few take up winter quarters in our plains, where snow is very rare, and there are countless little seeds to be picked up even in the heart of the cold season. The lark which searches wheat fields and fallows is one; another is the titlark, which prefers fields of luzern and meadows.
The skylark, so common in almost every part of France, does not nest in the plains of Vaucluse, where it is replaced by the crested lark—friend of the highway and of the road-mender. But it is not necessary to go far north to find the favourite places for its broods; the next department, the Drôme, is rich in its nests. Very probably, therefore, among the flocks of larks which take possession of our plains for all autumn and winter many come from no farther than the Drôme. They need only migrate into the next department to find plains that know not snow, and a certainty of little seeds. [[202]]
A like migration to a short distance seems to me to have caused the assemblage of Ammophila on the top of Mont Ventoux. I have proved that this insect spends the winter in the perfect state, sheltering somewhere and awaiting April to build its nest. Like the lark it must take precautions against the cold season; though capable of fasting till flowers return, the chilly thing must find protection against the deadly attacks of the cold. It must flee snowy districts, where the soil is deeply frozen, and, gathering in troops like migrant birds, cross hill and dale to seek a home in old walls and banks warmed by a southern sun. When the cold is gone, all or part of the band will return whence they came. This would explain the assemblage on Mont Ventoux. It was a migrant tribe, which, on its way from the cold land of the Drôme to descend into the warm plains of the olive, had to cross the deep, wide valley of the Toulourenc, and, surprised by the rain, halted on the mountain top. Apparently A. hirsuta has to migrate to escape winter cold. When the small migratory birds set out in flocks, it too must journey from a cold district to a neighbouring one which is warmer. Some valleys crossed, some mountains overpassed, and it finds the climate sought.
I have two other instances of extraordinary insect gatherings at great heights. I have seen the chapel on Mont Ventoux covered with seven-spotted ladybirds, as they are popularly called. These insects clung to the stone of walls and pavement so close together that the rude building looked, at a few paces off, like an object made of coral beads. I should not dare to say how many myriads were [[203]]assembled there. Certainly it was not food which had attracted these eaters of Aphidæ to the top of Mont Ventoux, some 6000 feet high. Vegetation is too scanty—never Aphis ventured up there.
Another time, in June, on the tableland of St. Amand, at a height of 734 mètres, I saw a similar gathering, only less numerous. At the most projecting part of the tableland, on the edge of an escarpment of perpendicular rocks, rises a cross with a pedestal of hewn stone. On every side of this pedestal, and on the rocks serving as its base, the very same beetle, the seven-spotted ladybird of Mont Ventoux, was gathered in legions. They were mostly quite still, but wherever the sunbeams struck there was a continuous exchange of place between the newcomers, who wanted to find room, and those resting, who took wing only to return after a short flight. Neither here any more than on the top of Mont Ventoux was there anything to explain the cause of these strange assemblages on arid spots without Aphidæ and noways attractive to Coccinellidæ,—nothing which could suggest the secret of these populous gatherings upon masonry standing at so great an elevation.
Have we here two examples of insect migration? Can there be a general meeting such as swallows hold before the day of their common departure? Were these rendezvous whence the cloud of ladybirds were to seek some district richer in food? It may be so, but it is very extraordinary. The ladybird has never been talked of for her love of travel. She seems a home-loving creature enough when we see her slaying the green-fly on rose trees, [[204]]and black-fly on beans, and yet with her short wings she mounts to the top of Ventoux and holds a general assembly where the swallow herself only ascends in her wildest flights. Why these gatherings at such heights? Why this liking for blocks of masonry? [[205]]