Unmown refuge areas and their influence on the survival of grassland birds in the Saone valley (France)

The objective of this study is to assess the attractiveness of refuge areas to the avifauna of the mown prairies in theVal de Saone region, after the disappearance of all cover by mowing. We compared the densities of several species, notably the corncrake, Crex crex, and the common quail, Coturnix corturnix, in three categories of refuge areas of unmown grasslands. Within the 10-m wide strips, covering in total 3-5% of the study area, bird densities at the beginning of August, after the hay-making season, are much higher than the densities recorded in the prairies during haymaking in July. Quail and corncrake densities are always lower, although still higher than the July densities in the prairie, in the fields of some 0.5 ha (covering 6.1% of another study area). In fields of 1 ha or more, the low densities of the two species reveal their poor attractiveness, or the absence of it. When during outside-in mowing some 10-m wide strips in the center of the fields are left uncut before the completion of mowing, or when during inside-out mowing two 5-m wide strips along the field margins are not mown, the contacts between the mowing machine and half of the unfledged young quails, and one-third of the unfledged young corncrakes, can be avoided.