Creating ephemeral resources: how long do the beneficial effects of grass cutting last for birds?

Abstract

CapsuleBeneficial effects of cutting grass are relatively short-lived for a range of bird species. AimsTo investigate how cutting affects a range of birds occurring on farmland, how long these effects last, and whether there is any effect of the timing of cutting operations. MethodsWe surveyed birds on 33 grass fields on three farms in northern England, both before and after agricultural cutting operations. The data were then modelled using generalized linear mixed models (GLMMs). Results Species relying on below-ground invertebrates (e.g. corvid species) prefer cut swards, while some species make greater use of longer grass swards (e.g. pheasant). Use of fields after cutting declined by 50 % by day 11 for corvids, by day 8 for aerial feeders (e.g. hirundines), by day 6 for gulls, and by day 4 for kestrels. ConclusionsWe recorded mainly common, generalist species that make use of agricultural grassland. The foraging behaviour of these species is similar to other, rarer or declining species, and so our findings can be extrapolated to a range of farmland birds. However, it is important to note that some studies indicate direct negative effects of cutting on some species not found in our surveys.