Management of cover areas may increase numbers of breeding Corncrakes Crex crex

Abstract

Capsule Density of Corncrakes is greater in areas of positively managed non‐crop cover vegetation which occur alongside fields managed to enhance breeding success.

ACKNOWLEDGEMENTS

Many thanks to James How, Tom Epps, Craig Archibald, Cath Fotheringham, Michael Coppleston, Michael Sur, Eion Brown, Andy Schofield, Dr Patrick Doncaster and John Jones. Many thanks to two reviewers, whose suggestions greatly improved the manuscript.

Notes

a. Number and density of Corncrakes was calculated from the number of birds found across the entire area of each farm and the entire area of cover and silage habitat within each farm (Table 1).

b. Differences in June density in cover habitat across farms were not found to be significant (χ² = 3.0, P = 2.0), while differences in silage habitat across farms and differences across farms irrespective of habitat type were found to be highly significant (χ² = 90.0, P = 0.001 and χ² = 32.9, P = 0.001, respectively). Differences in June sward height in cover habitat across farms (χ² = 18.6), in silage habitat across farms (χ² = 93.8) and across farms irrespective of habitat type (χ² = 73.1) were all found to be highly significant (P = 0.001). Differences in August density across farms (χ² = 17.7) and sward height across farms (χ² = 15.5) were also found to be highly significant (P = 0.001).

c. Significant differences between farms in mean percentage cover of several species were identified by Friedman’s test: June and August cover areas of U. dioica, (χ² = 21.3, P = 0.001 and χ² = 10.2, P = 0.006, respectively); Heracleum spp. (χ² = 10.8, P = 0.005 and χ² = 8.9, P = 0.012, respectively), Phalaris spp. (χ² = 18.0, P = 0.001 and χ² = 18.5, P = 0.001), Cynaeae spp. (χ² = 7.28, P = 0.026 and χ² = 17.6, P = 0.001) and of Juncus spp. August cover and silage (χ² = 7.4, P = 0.025 and χ² = 14.9, P = 0.001, respectively).