Availability of weed seeds and waste cereals to birds on arable fields during spring

There is increasing concern and evidence that modern agricultural practices have reduced the availability of weed seeds and waste cereal grains on arable fields during the winter. However, we believe that early spring may be another bottleneck for food availability for granivorous birds. During March 1996 and 1997 we collected nearly 300 0.25m(2) by 1 cm deep soil samples from arable and set-aside fields on 16 sites across southern and eastern England to assess availability of seeds to birds. Total seed numbers varied by site (P<0.001), year (P<0.002) and crop type (P=0.067). Set-aside contained more seeds than winter or spring tilled fields. Waste grain densities were low in all field types and were found in only 7.8% of samples. Our data suggest that the seed bank available in arable fields during spring is insufficient to maintain adequate food resources for pheasants and other granivorous birds, but that set-aside, although extremely variable, might help mitigate these problems if managed carefully.