The latest Breeding Bird Survey for the British Trust for Ornithology (BTO), in partnership with the Royal Society for the Protection of Birds (RSPB) and the Joint Nature Conservation Committee, has highlighted a significant decline in woodland bird species, writes the woodlands.co.uk blog.
It says that the annual survey has revealed numbers down by more than 50% in several species, the worst hit being the willow tit down by 77%.
The reason for the decline is not obvious, the blog adds.
“It isn’t due to loss of habitat – there is more woodland in the UK today than there has ever been, and, on the whole, modern woodland management is more sympathetic to environmental concerns.
“The Farm Woodland Scheme and Farm Woodland Premium Scheme have also encouraged the planting of small woodlands.”
It suggests the fall in breeding woodland bird species may be the result of a change to the composition and structure of the UK’s woodlands.
“Traditional methods of management such as coppicing provide a perfect habitat for warblers and nightingales, for instance,” woodlands.co.uk reports.
“The coppicing process whereby the wood is regularly cut back creates open woodland with plenty of undergrowth for nesting. Where coppice is left to grow unchecked, eventually the canopy closes and the undergrowth is shaded out.
“Mature woodland with a closed canopy supports tree-dwelling birds such as the woodpecker, but offers a less diverse selection of species overall.”
The blog highlights a possible connection between the fall in bird numbers and the growing population of deer: “Many woodland species like the woodland edges and open areas where there is shrubby, low-level cover.
“An explosion in the number of deer in the UK has had a noticeable impact on just this sort of habitat through grazing at the herb and low shrub level. It is quite likely that this is making a serious impact on woodland bird numbers.”
Migration has also been suggested as a factor.
Several British woodland birds, such as the wood warbler, are annual summer visitors that overwinter in sub-Saharan Africa. It has been suggested that drought in that region may be having an effect.
Citing studies in the Netherlands, the blog post by Catherine also suggested that reduction of habitat quality through traffic noise from nearby roads could have significantly affected local woodland bird populations.