The birds along twenty 500 m lengths of coastal borrowdyke (water-filled ditches left when clay is extracted to make a sea wall) in eastern England were counted in spring 2004 and occurrence related to features of habitat. A total of 45 species was recorded with species richness ranging from 5–21. The most widespread species were little grebe Tachybaptus ruficollis, mute swan Cygnus olor, mallard Anas platyrhynchos, moorhen Gallinula chloropus, coot Fulica atra, sedge warbler Acrocephalus schoenobaenus, reed warbler Acrocephalus scirpaceus and reed bunting Emberiza schoeniclus, all typical wetland birds. Of 20 habitat variables measured, six (open water, narrow and broad marginal Scirpus, width, and low and tall thick scrub) were significant in describing species abundance data in a Canoco analysis. The linear coastal habitat of borrowdykes is regionally important for the conservation of some wetland species and current rotational management for land drainage purposes maintains the variety of habitats to retain a diversity of bird species.
The distribution and number of colonies of rooks Corvus frugilegus L. was studied over a three-year period in a landscape in eastern England dominated by winter cereals. Individual rookeries were generally small and not evenly distributed, with a total of 1561– 1637 nests in a 325 km2 study area over the three years. The distribution of groups of rookeries (main colony with satellites) was associated with the amount of grassland, a colony of 100 nests requiring some 122 ha of grass within 1 km. Feeding habitat and preferences of rooks were studied throughout one year. The most consistently used feeding habitat was grassland and it was strongly preferred, with a peak in June. Winter cereals were used from October to March, but were never preferred, other crops being used seasonally. Flock size peaked in February and was smallest during the breeding season, when the mean distance of feeding flocks from the colony was less than 1 km. Increases in land given over to horses, riding and turf production could benefit rooks in the study area.