Habitats of the song thrush Turdus philomelos in a largely arable landscape

Abstract

During three breeding seasons, 1994±96, the habitats of song thrushes were studied in north-east Essex, U.K., in 10 tetrads (total 40 km 2 ) of mainly farmland habitat and 35 woods of differing sizes (range 0.1± 57.0 ha). Within tetrads, only 6 (3.5%) territories were found in farmland. Gardens held 123 (71.5%) territories, though this habitat made up only 2% of the total area, while 39 (22.7%) were in woodlands (1% of total area). Population densities were much lower in the tetrads than in earlier studies; this may be an indication of the severe population decline that the species has recently undergone. Densities in gardens differed less from those of previous studies.In the woodland study, the number of woods holding song thrush territories declined over the three years, while the proportion of total territories in the six largest woods increased. Densities in the woods were lower than those reported in earlier studies but the disparity was not as great as in farmland. Extinctions in the smaller woods was 20±30% per annum, a rate similar to that for gardens: population extinctions did not occur in the larger woods.Some 40% of non-garden territories in the surveys of both tetrads and woodland plots were within 100 m of a garden. Gardens may be currently acting as a refuge for song thrushes and an understanding of the ecology of the species in different types of gardens may be important in current conservation efforts for the species.

Avian species richness and numbers in the built environment: can new housing developments be good for birds?

“…Some species, such as song thrush and blackbird, have largely disappeared from farmland (Mason 1998(Mason , 2000 and the present study confirms this situation, with song thrush being absent from farmland and blackbird scarcer here than in all other plots. Song thrushes were most numerous in village and urban green corridor plots.…”

“…Some species which have largely disappeared from farmland in eastern England, such as the thrushes, appear to be thriving in the built environment (Mason 1998(Mason , 2000(Mason , 2003, while it has been estimated that habitats associated with human habitation hold more than 20% of the total population of some species in Britain (Gregory and Baillie 1998). Nevertheless, two typically urban species, starling Sturnus vulgaris and house sparrow Passer domesticus, have been added to the red list of birds of conservation concern in the UK because of strong population declines (Gregory et al 2003).…”

Habitat selection by song thrushes in stable and declining farmland populations

“…The decline has been greatest on farmland (approximately 70% of pairs lost) but also pronounced in lowland woodlands ( c. 50% of pairs lost). Densities of breeding song thrushes are now low on most intensively managed arable farmland, with the majority of remaining territories associated either with gardens or woodland (Mason 1998). Extensive demographic data indicate no long-term changes in nesting success per attempt (Baillie et al .…”

“…A diverse range of environmental factors may have had negative impacts on farmland song thrushes. These include loss and degradation of key feeding and nesting habitats (Mason 1998), increased depredation of nests and fully grown thrushes from increasing populations of avian and mammalian predators (Thomson et al . 1998;Paradis et al .…”

“…1998;Paradis et al . 2000;Stoate & Szczur 2001), dry summer weather (Mason 1998) and direct and indirect effects of pesticides (Campbell et al . 1997).…”