Tuesday 19 April 2016

Nests

My "Nature Notes" contribution for the month to come . . . my second on this subject.

Most children believe that birds live in nests - or at least, they do when they are very young. If they are interested in nature they will soon come to realise the truth - so far as nearly all birds are concerned - that nests are very temporary structures, used only for the brooding of eggs and the nurturing of chicks. But just now the nesting season is in full force, and nests will be in use.

There are many variations on the basic nest template. Some birds make virtually no nest, with some coastal or seabirds, for example,  more or less nesting directly on rock ledges, or in a scrape on a pebble beach. And then there is the cuckoo, of course, which doesn’t bother with making its own nest - or indeed caring for its own offspring - but parasitises on others.

Garden birds do make nests, which vary from the flimsy jerry-built bundles of twigs that are the nearest that pigeons get to nests, to the amazingly detailed little domed nests of long-tailed tits. These small masterpieces can take a couple of weeks to build (or, better perhaps, to weave) - they are soft and warm, made from moss, hair, wool, and maybe a thousand or more feathers. It is usually very well concealed, in the fork of a tree or in thick brambles. But even such a fine and detailed nest is only used by the baby birds for some two to three weeks.

Another very detailed nest is that of the wren, made of grass, moss and leaves. In many birds it is the female that takes the lead in nest-building, while the male spends most of his time defending the territory. In wrens, however, it is the male who builds, and he will in fact build several nests, often quite inventively sited, and the female will then choose the nest she wants to use. Wrens will on occasion use their nests as winter shelters in very cold weather when their small size makes them vulnerable.

Most nests are carefully hidden away, but inexperience and pressure for nest spaces may mean birds build in places that are too obvious, and if you know where a nest is, then predators probably do as well. Nests are at risk from magpies, crows, cats, rats, squirrels, even wood-peckers. Try and keep some thick bushy cover in your garden if you want breeding birds in spring as well as feeding birds in winter. Nest-boxes will benefit many birds which like to seek out holes in which to build their nests - like tits, nuthatches and sparrows. House sparrows like to nest together, and multiple occupancy sparrow boxes can be bought. Other social nesters include jackdaws and rooks - social but not always sociable, as jackdaws will take over the nests of neighbours, and rooks are notorious stealers of twigs - and of course swallows and martins.

Finally, a little mention of the robin, one of our most entertaining nesters. Robins will often nest in sheds and outbuildings, and use buckets, pans, kettles as shelter! Most years a robin or two will make the news with their amusing choice of nest site.

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