Most persons are familiar with those companies of small birds which form in woods in winter, composed of tits of all species, with siskins, goldcrests, and sometimes other kinds. The July gatherings are larger, include more species, and do not travel incessantly like the winter companies. They are composed of families--parent birds and their young, {91} lately out of the nest, brought to the oaks to be fed on caterpillars. It may be that their food is more abundant at certain points, but it is also probable that their social disposition causes them to congregate. Walking in the silent woods you begin to hear them at a considerable distance ahead--a great variety of sounds, mostly of that shrill, sharp, penetrative character which is common to many young passerine birds when calling to be fed. The birds will sometimes be found distributed over an acre of ground, a family or two occupying every large oak tree--tits, finches, warblers, the tree-creeper, nuthatch, and the jay. What, one asks, is the jay doing in such company? He is feeding at the same table, and certainly not on them. All, jays included, are occupied with the same business, minutely examining each cluster of leaves, picking off every green caterpillar, and extracting the chrysalids from every rolled-up leaf. The airy little leaf-warblers and the tits do this very deftly; the heavier birds are obliged to advance with caution along the twig until by stretching the neck they can reach their prey lurking in the green cluster, and thrust their beaks into each little green web-fastened cylinder. But all are doing the same thing in pretty much the same way. While the old birds are gathering food, the young, sitting in branches close by, are incessantly clamouring to be fed, their various calls making a tempest of shrill and querulous sounds in the wood. And the shrillest of all are the long-tailed tits; these will not sit still and wait like the others, {92} but all, a dozen or fifteen to a brood, hurry after their busy parents, all the time sending out those needles of sound in showers. Of hard-billed birds the chaffinch, as usual, was the most numerous, but there were, to my surprise, many yellowhammers; all these, like the rest, with their newly brought out young. The presence of the hawfinch was another surprise; and here I noticed that the hunger call of the young hawfinch is the loudest of all--a measured, powerful, metallic chirp, heard high above the shrill hubbub. [Sidenote: Caterpillars and ants]