Bird Tree
Trees provide birds with song-posts, roost-sites, nesting-places and food, either directly through their seeds, nuts or fruits, or indirectly through the insects they attract. Anything with reasonably thick foliage might provide a roost-site; ornamental evergreens are best for this, but beyond planting a few of these there are not much you can do. You should not worry too much about providing song-posts; most birds will use whatever is available, including roofs, television aerials, wires, as wells trees and bushes.
As far as possible, existing trees—especially native or long-established kinds—should be retained. Ideally, too, you should not be in too much of a hurry to remove dead wood as this can often provide useful insect food and potential nest-holes for several species. If you have enough room, elm is a thoroughly worthwhile tree and even one with Dutch elm disease, though unsightly, will be of benefit to birds for several years after its infection and death. If it is safe, think about retaining it for a time.
Trees to retain and trees to plant can be dealt with together. Important considerations in both cases are preferred soil type, eventual height and size and the likely spread of the tree—and whether it is safe to have it close tithe house. Remember, too, that many trees are relatively slow-growing and will not reach maturity for a long time. Big trees really belong in big gardens. For most people, smaller species have to do instead—but many of these are of equal value to birds.
Small ornamental conifers and maples, while very popular, are of limited value to birds, except that they provide some cover and nest-sites. Most are of little value for food. Native or well-established species are far better. The oak quarks robber is used by some 300 species of insects, provides nest-sites and grows acorns which are much appreciated by wood pigeons and jays. Willows too are immensely rich, with some 250 insect species recorded and a useful supply of seeds in the autumn. As with oaks, some of the ornamental varieties are almost as good as the native kinds. Poplars may have up to 100insect species on them; silver birch can have as many as 225 and its catkins provide good spring feeding for red polls and other small birds. Beech trees provide nuts in autumn—the popular beech mast which is eagerly sought-after by, among others, chaffinches, green finches and winter-visiting brambling. More than any other tree, perhaps, the hornbeam is likely to attract the shy and delusive hawfinch, especially if there are several trees together and a drinking pool nearby. Ash is another useful tree: bullfinches are particularly fond of ash-keys. The rowan or mountain ash would be a beautiful garden tree even if its berries attracted no birds at all—but thrushes and blackbirds love them!
Cherry trees of various kinds, crab apples and several ornamental trees in the white beam group all produce fruits which are attractive to birds, especially thrushes, sometimes hawfinches and, in the occasional winters when they appear in large numbers, waxwings. Holly provides excellent cover, roosting and nesting places and berries. Gardeners (unless they are also avid wine-makers) tend to look askance at elder, but it is a good berry-bearing and insect-rich species, favored by many small birds in autumn especially. Hazel, too, is a good tree for its cover and its nuts. There are, in fact, many more useful trees in the broadleaf group: spindle, the limes, wayfaring tree, bird cherry, and field maple, for instance.
Alder, which likes wet or very damp places and is a likely species alongside rivers or lakes. It is another very rich ‘bird tree’, popular with tits, warblers, tree creepers and, especially, redpolls and sissies.
Of the conifers, yew is one of the best, providing thick cover and berries which, while they are harmful to man and domestic animals, are eaten by many birds like thrushes and greenfinches. Coal fits and gold crests feed on the insects in yews and also in the native Scots pine. This handsome tree (and several of its close relatives) produces cones which also attract coal tits (and crested its) and, of course, crossbills. Both the European and theJapaneses larches are similarly excellent trees for birds—and so, in fact, are many of the larger exotic conifers widely planted in bigger gardens, such as cedars and redwoods.
Apples in particular area favorite of many birds, such as thrushes and waxwings. Bullfinches may damage the buds in spring, of course, making them unpopular with gardeners at that time. If you can, leave a few apples on the trees for the birds, and some windfalls on the ground.
Ivy, which grows both on trees and on houses. It actually does little harm to trees, despite popular opinion, and can be kept within reasonable bounds on walls. Few plants are as good for birds: ivy provides cover, nest-sites for many species (eg. blackbirds, song thrushes, robins and spotted flycatchers), a rich variety of insect food and a late and welcome supply of berries from January to March.