Delayed mowing increases corn bunting Emberiza calandra nest success in an agri-environment scheme trial

摘要: Abstract Management intensification in agricultural grasslands is a major conservation concern. During the last 50 years, meadows have been drained, re-seeded with high-yielding grasses, treated chemicals to remove pests and promote rapid growth, mowing has become earlier more frequent. This severely reduced reproductive success of several meadow-nesting bird species across large areas Europe, causing population declines. Corn buntings Emberiza calandra excluded from nesting much north-western Europe by tend persist only later-harvested cereal crops. However, where persists, adjustment dates supported agri-environment schemes could still be critical measure for remaining populations. Using trial interventions, we tested relationship between delayed 19 mixed arable/grassland farms main range corn Scotland, over five breeding seasons. require around weeks nest building fledging, Scotland start during mid-May–June. Delayed 1 August (6–8 after mean first egg date attempts meadows) significantly increased probability brood fledging (0.282, compared 0.034 fields mown June or July), potential population-wide effect raising overall productivity all crop types 20%. To reach level required stability (1 successful per female), estimate that at least 40–50% nests must mowing. With effective targeting, this achieved just 10–20% (260–520 ha throughout species’ northeast range), cost £100 000–£160 000 year.