Friday, 2 April 2010

Nesting birds

The peak time for breeding birds will soon begin . Many large nests can be seen  high in the canopy, with  fewer small nests in the less mature birch.


One ground nesting bird is the pheasant, which is regularly seen in the wood. The nest is little more than a hollow  scrape in the ground, scantily lined with leaves and grass. 8-12 olive brown eggs are usually lain mid April - May. Incubation takes just over 3 weeks and the hatchlings leave the nest shortly afterwards, being tended by the female. The female is very well camouflaged.

The woodcock, although lacking their preferred field layer, may use bracken as cover . They nest near their favourite swampy feeding sites, a scrape on the ground lined with dead leaves, often by a tree . The olive brown eggs with dark markings, usually four, are incubated for three weeks. The nestlings depart shortly after hatching, tended by their parents and flying after two weeks. Adults may be observed carrying young to safety.Both eggs and nestlings of these ground nesting species are at high risk of predation by foxes.

 The robin may nest in dense vegetation from ground level up to about 3m, from March - July. Nests are  difficult to find, but may be traceable when adult birds are feeding the young.The wren , a small and noisy bird typically nests April - July within 2m of the ground, in dense, low cover or concealed against a tree trunk in honeysuckle, a dominant climber within the woodland.  Both these species also nest in brash piles.

Blackbirds are ground feeders  generally nesting low in the shrub layer, seldom higher than 4 m. Their breeding season is March - July. The song thrush nests in similar locations. Both line their nests with mud, but the blackbird finishes with an additional layer of grass. The blackbird has a foundation of moss whilst the song thrush base is small twigs. This nest, found in rhododendron during removal, is probably blackbird.

There are many hole nesting species in the wood, many of whom nest at a relatively low level. The marsh tit excavates its own hole in a live tree , typically within 3m of the ground. It often feeds at a low level , either on the ground or within the shrub layer or low canopy. This bird rarely uses nest boxes. Blue tits and great tits typically nest at a higher level, up to 15m. These species can easily be 'watched back' to identify nest sites both when building nests and feeding chicks. The blue tit is predominantly a canopy feeder while the great tit prefers the lower shrub layer.

While these birds are predominantly associated with broad leaved woodland, the coal tit is often associated with coniferous woodland. It is another hole nester but will frequently use holes at ground level, in tree roots and stumps, as well as natural tree crevices up to 5m high. Tree roots under an overhanging bank are a particular favourite, so could be nesting by the pond path. The long tailed tit is not a hole nester, but builds an intricate oval nest woven from moss, cobwebs and hair and lined with feathers. It has a small entrance hole near the top of the nest. This may be situated in a dense, thorny thicket or hedge, or sometimes in the fork of a tree, although it may be well camouflaged by lichen and difficult to spot. Breeding is from April - May, but nest building may begin as early as late February.All these tits breed April-June.

Both the green and great spotted woodpecker use holes excavated in live trees. Calls and 'chasing' displays are signs of courtship activity, as well as drumming. Materials are not carried into the nest site but wood chips at the bottom of a tree are a telltale sign. The green woodpecker breeds April-June, with the great spotted woodpecker a little later, in May-July.

The nuthatch also uses holes in trees, but will plaster with mud to reduce the entrance size, making the nest distinctive if found. A pair have already been seen calling to each other in the alder, but they become silent once eggs are laid. Breeding is late April-June, so nest sites may be difficult to spot at the feeding stage, as foliage on the trees will obscure likely holes.

The treecreeper is another April-June breeder, using crevices in bark or between roots of ivy on a tree trunk, rather than holes. Nest height is 1-3m. Look for protruding pieces of nesting material.

The finches may nest in either bushes or trees at a wide range of heights. The most likely woodland nester is the chaffinch, whose nest is notably neat. Songs and display flights are possible indicators of a nearby nest site. All finches nest between April-July. Greenfinch and bullfinch have also been seen in the woodland.

The tiny goldcrest nest usually hangs below a branch and may be high in the conifer canopy or at a lower level in gorse, honeysuckle or ivy in broadleaved sites. Breeding time is April-June.

Crows, magpies and wood pigeon may already be nesting high in the canopy. Jays breed late April-June, but the bowl shaped nest is difficult to find, usually in cover. Their raucous calls may be the best indicator of their presence.

An important aim of  woodland management is to improve the habitat for wildlife and increase biodiversity. Observations form a baseline for future changes to nesting records, which will be a key indicator of  success. This information will also feed into the national picture by contributing to the breeding bird survey run by the BTO (British Trust for Ornithology). Signs of returning summer migrants will be looked for, such as blackcap or chiffchaff, which may use the wood for feeding or nesting purposes. 

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