The effect of mowing on next-year predation of grassland bird nests: experimental study

The effect of mowing on nextyear nest predation was studied in grassland areas on the outskirts of Cracow (south Poland). In 2004 and 2005, nesting success at three sites with two plots each – one unmowed for 2–3 years and one mowed every year – was assessed experimentally with artificial nests baited with two Japanese Quail Coturnix japonica L. eggs. Biomass samples were collected for estimations of the standing crop of vegetation. Mowing was found to be correlated with nest predation pressure on the unmowed plots in two meadows that had greater vegetation cover. At the third site, nest predation and vegetation cover did not differ between the mowed and unmowed plots. All selected sites were classified as Arrhenatherum elatius grassland. Also birds communities of study sites were similar in regard to occurrence of small ground-nesting passerine species: Grasshopper Warbler Locustella naevia Bodd., Reed Bunting Emberiza schoeniclus L., Whinchat Saxicola rubetra L., Yellow Wagtail Motacilla flava L. Artificial nests were destroyed mainly by corvids and only few percent were recognized as destroyed by mammals. The intensity of nest destruction differed greatly between years, probably because Magpies Pica pica L. were less active in 2005.