Background information and definitions
During mowing and harvesting operations, ground-nesting birds frequently remain in long grass or crops for as long as possible. If mowing/harvest occurs from the outside of the field inwards, this behaviour can leave the birds trapped in the centre of the field and killed as the last patch is harvested. However, if unharvested refuges are left in fields then it is possible that chicks and adults will remain in them and survive.
Supporting evidence from individual studies
A replicated study in 1996-7 in 62 hay fields in Bourgogne, France (Broyer 2003), found that contact between mowing machinery and unfledged common quail Coturnix coturnix and corncrake Crex crex was reduced by approximately 50% and 33% respectively, by leaving 10 m wide, uncut strips in the centre of fields. In addition, unmowed strips held the highest concentrations of corncrakes, quails and passerines (7.7 birds/ha, 3.8 birds/ha and 10.8 birds/ha respectively in 1996).Study and other actions tested
A review of four experiments on the effects of agri-environment measures on livestock farms in the UK (Buckingham et al. 2010) found one trial from 2006 to 2008 demonstrating that uncut nesting refuges for skylarks Alauda arvensis in silage fields were not used more than other areas. Refuge plots of 1 ha were cut with raised mowing height in the first silage cut, then left uncut for the rest of the season. The plots were preferred for re-nesting for two weeks following the first cut, but subsequently did not have higher nest densities than other areas. Skylarks continually re-nest rather than re-nesting in a batch after each cut. After the second cut, safe areas were completely avoided by skylarks. This study formed part of a Defra-funded project (BD1454) for which no reference is given in the review.Study and other actions tested