Before going into this part of my subject it would be useful to briefly summarise the main facts disclosed in the foregoing chapters.
1. Many species formerly resident throughout the year in London have quite died out; thus, in the present century the following large species have been lost: raven, magpie, peregrine falcon, and kestrel. In very recent years the following small resident species have disappeared from inner London, but are still found in a few localities on the outskirts: missel-thrush, nuthatch, tree-creeper, oxeye, and lesser spotted woodpecker.
2. Some resident species are reduced to small remnants and are confined to one or to a very few spots; in this category we must place the rook, the jackdaw, and the owl.
3. Several other resident species, formerly common, have greatly decreased in numbers, and in some of the open spaces appear to be dying out. Among these are the thrush, blackbird, robin, wren, hedge-sparrow, greenfinch, chaffinch, goldfinch, bullfinch, linnet, and lark. Two of these species, thrush and blackbird, are now increasing in several of the open spaces under the County Council, and here and there two or three of the other species named are also increasing.
CHAFFINCH
4. The decrease has been in most, but not all, of the old residents. So far the carrion crow does not appear to have suffered. Two small birds, sparrow and starling, have undoubtedly greatly increased.
5. At the same time that some of the old residents have been decreasing or dying out, a few other species have come in from the outside, and have greatly increased—namely, the ringdove, moorhen, and dabchick.
6. During the season when birds migrate, or shift their quarters, many birds of various species drift into or pass through London: of these some that are summer visitors bred regularly in London up to within a few years ago. Of all these visitors it may be said that they have been decreasing for several years past, and some of them no longer attempt to breed in the inner London parks. At the same time, in a few favoured localities these visitors do not show any falling off, and in one or two of the open spaces they may be actually increasing.