Secondly, although so many successive `throws' of timber thinned out the trees, yet there may still be found more groups and rows of elms and oak in this direction than in any other; that is, a line drawn northwards from the remaining wood passes through a belt of well-timbered country. On other side of this belt there is much less timber; so that the rooks that desired to build nests beyond the limits of the enclosed wood still found in the old places the best trees for their purpose. Here may be seen far more rookeries than in any other direction. Hardly a farmhouse lying near this belt but has got its rookery, large or small. Once these rookeries were established, an inducement to follow this route would arise in the invariable habit of the birds of visiting their nesting-trees even when the actual nesting time is past. Thirdly, if the inquiry be carried still farther back, it is possible that the line taken by the rooks indicates the line of the first clearings in very early days. The clearing away of trees and underwood, by opening the ground and rendering it accessible, must be very attractive to birds, and rooks are particularly fond of following the plough. Now although the district is at present chiefly meadow land, numbers of these meadows were originally ploughed fields, of which there is evidence in the surface of the fields themselves, where the regular `lands' and furrows are distinctly visible. One or all of these suggestions may perhaps account for the course followed by the rooks. In any case it seems natural to look for the reason in the trees. The same idea applies to the other stream of rooks which leaves the wood for the eastward every morning, flying along the downs. In describing the hill district, evidence was given of the existence of woods or forest land upon the downs in the olden time. Detached copses and small woods are still to be found; and it happens that a part of this district, in the line of the eastward flighty belonged to a `chase' of which several written notices are extant. The habits of rooks seem more regular in winter than in summer. In winter the flocks going out in the morning or returning in the evening appear to pass nearly at the same hour day after day. But in summer they often stay about late. This last summer [1878] I noticed a whole flock, some hundreds in number, remaining out till late--till quite dusk--night after night, and always in the same place. It was an arable field, and there they stood close together on the ground, so close that in spots it was difficult to distinguish individuals. They were silent and still, making no apparent attempt at feeding. The only motion I observed was when a few birds arrived and alighted among them. Where they thus crowded together the earth was literally black.