Data from: Winter game crop plots for gamebirds retain hedgerow breeding songbirds in an improved grassland landscape

The cause of recent population declines in some farmland / hedgerow
breeding bird species in the UK is related to a lack of cover and food
resources in winter.  In improved grassland areas some of those
declines have been particularly acute and some have been shown to be
related to the availability of grass and weed seed in winter. 
The provision of seed-bearing crops as part of AES options has been shown
to benefit some of these birds.  Game crop plots sown on shooting
estates for holding and driving gamebirds in autumn and winter have been
shown to hold relatively high densities of farmland and wood-edge birds
during the winter. We studied breeding songbirds in hedges in a primarily
improved grassland area in the SW of England where there are some large
shooting estates that sow relatively large game crop plots (1 - 5 ha) in
the landscape.  In this study we found that otherwise similar
hedges in terms of size and density near to those winter game crop plots,
had between 1.5 and 2 times as many breeding resident songbirds per unit
length the following spring compared to hedges further away from game crop
plots. This was despite game management in these plots being wound down
during February and in many cases, the crops themselves being removed by
mid-March. Hedges within approximately 350m from game crop plots had more
breeding birds. We discuss possible mechanisms and suggest that some
passerines preferentially establish breeding territories in hedges near to
game crops in late winter. We suggest how to distribute game crop plots to
maximise any benefit in an improved grassland landscape.