Individual study: Comparative quality of winter food sources for cirl bunting delivered through countryside stewardship special project and cs arable options
N. (0) Comparative quality of winter food sources for cirl bunting delivered through countryside stewardship special project and cs arable options.
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Leave overwinter stubbles
A replicated, randomised study from November 2003 to March 2004 in 205 cereal stubble fields under a range of management intensities in arable farmland in south Devon, UK (Defra 2004), found that barley stubbles following low-input herbicide were more beneficial for cirl buntings Emberiza cirlus than wheat or conventionally managed stubbles. Higher population sizes were also associated with the number of breeding bunting territories the previous season, and with small field size. The effect of small field size may be because cirl buntings prefer to forage near hedgerows and because smaller fields are less intensively managed. The authors argue for strategic spatial targeting of stubble prescriptions. Overall, barley fields were generally preferred by seed-eating species. Low-input barley stubbles had significantly higher seed abundance and broad-leaved weed cover (approximately four times greater). Fields where stubbles were grazed over winter had significantly lower densities of seed-eating birds in general. The authors point out that seed-eating species’ preference for barley stubbles was independent from the positive correlation with broad-leaved weed density and should be taken into account when planning prescriptions.
Plant wild bird seed or cover mixture
A replicated, randomised study between November 2003 and March 2004 in 205 cereal stubble fields under a range of management intensities in arable farmland in south Devon, UK (Defra 2004) found no clear changes in habitat use by seed-eating birds after the establishment of wild bird cover crops on some stubble fields. The target species, cirl bunting Emberiza cirlus, made insignificant use of wild bird cover crops (average of two individuals/plot). Only two plots contained >5 individuals and use of the habitat dropped drastically in March, which the authors suggest makes the habitat a poor alternative to stubbles. High numbers of other seed-eating species were recorded on the wild bird cover crops, especially those containing a mixture of rape, millet, linseed, kale and quinoa (maximum seed-eating bird count = 491 vs. 191 on barley fields). Only song thrush Turdus philomelos abundance was significantly positively related to wild bird cover presence. However, few stubble fields contained wild bird cover crops (13 fields with 24 wild bird cover strips) and the results may have been confounded by low sample size.