Birds of deciduous woodlands
The towering multi-layered structure of our woodland provides, in compact form, all the essential requirements of bird life-places to roost, nest and feed. Correspondingly, woods cater for a wide diversity of birds compared with more open, less structured habitats. The most densely populated zone is the shrub layer, the abundant insect life of which attracts tits, wrens and warblers in the summer. Some visit the high canopy which likewise harbours a rich store of caterpillars and aphids. The trunks and heavier limbs between these zones are the haunt of woodpeckers, nuthatches and treecreepers, while on the ground thrushes, robins, finches and jays rummage for fruits and invertebrates among the leaf litter.
Birds can often signal rather conspicuously the differences in woodland types. Redstarts, pied flycatchers and wood warblers, for instance, are quite common in the sessile oakwoods in western Britain, but are scarce or absent in the pedunculate oakwoods farther east. On a more local scale we can, with the passage of time, readily detect dramatic changes in the composition of birds in a given deciduous wood. Not least of these is the change wrought by the seasonal cycle of leaf production. Leaf emergence in spring is associated with a sudden and enormous increase in the insect food available, and a great influx of migrants, notably warblers, arrive from their African and Mediterranean winter quarters to swell the ranks.
At this time deciduous woods ring with bird song, the beauty of which, however, belies the earnest endeavour of the songsters to stake out territories, ward off rivals and attract mates. The bulk of the birds’ efforts are concentrated in the dawn hours, often spearheaded before sunrise by the songs of the dunnock and robin. Many woodland specialists, such as the jay and redstart, sport a bright flash of colour, the better to spot one another in the dim light.
By June the summer flush of insects is at its peak, supporting a new generation of fledglings. Thereafter, breeding activity wanes and high summer finds woodlands silent. The insectivorous migrants drift south again, almost overlapping with a new wave of immigrants – redwings, fieldfares, bramblings and redpolls.
- Bird Habitat (birdwatchtips.info)