Unknown reasons

In a sense, understanding the decline in most farmland birds has been easy, with relatively straightforward prescriptions for action. Other groups of birds, however, are also dropping in population or decreasing their range, especially woodland species and summer migrants. Much less attention has been paid to them and more research is urgently needed to understand the causes of their declines.

This Atlas shows that a number of species associated with lowland woods have decreased in the county, including Woodcock, Lesser Spotted Woodpecker, Spotted Flycatcher, Marsh Tit, Willow Tit and Lesser Redpoll. Although they all use woodland, their specific habitat requirements differ greatly and it is likely that different factors, probably acting in combination, are responsible. Fuller et al. (2005) identified seven probable causes, needing further study: (i) pressures on migrants during migration or in winter; (ii) climate change on the breeding grounds; (iii) general reduction in invertebrate food supplies; (iv) impacts of land use on woodland edges, habitats adjacent to woodland and hedgerows; (v) reduced management of lowland woodland; (vi) intensified habitat modification by deer; and (vii) increased predation pressure from Grey Squirrels, Great Spotted Woodpeckers and corvids. Six of these national factors could apply here, but probably nowhere in Cheshire and Wirral has yet suffered significant pressure from deer (Cheshire Mammal Group 2008), contrasting with some other parts of England where much woodland understorey has been lost, and comparisons between the county and elsewhere in England could be fruitful.

Another group of migrant species especially found in the western Atlantic oakwoods—Tree Pipit, Wood Warbler, Redstart and Pied Flycatcher—are also in decline, for reasons that are largely unknown.