Wader chick condition is not limited by resource availability on wader-friendly lowland wet grassland sites in the UK

Many wader species breeding on lowland wet grassland in Western Europe are becoming increasingly restricted to wader-friendly protected sites and nature reserves where habitat conditions and management methods are more suitable compared to those in the wider countryside. Breeding success is still low on these protected sites, which often leads site managers and policymakers to ask whether low food availability might be limiting chick survival despite management aimed at providing optimum foraging conditions. Although this question is difficult to answer on a large scale, here we attempt to do so by monitoring and comparing wader chick body condition and rates of growth across a range of UK sites, expecting that chicks in resource-limited areas will grow slower and weigh less than average for their age (be of lower body condition) than those in optimum foraging areas. We demonstrate that, on average, Northern Lapwing Vanellus vanellus and Common Redshank Tringa totanus chicks achieved growth
rates similar to those calculated for larger samples of chicks studied during the past four decades in The Netherlands and the UK, and achieved greater condition than expected based on standardized measures from a previous Dutch study. This suggests that food availability for chicks on well-managed lowland wet grassland sites is unlikely to be the factor limiting chick survival and population recovery of wader species in this habitat. Instead we should be more concerned about other potential causes of chick mortality, such as predation or agricultural activities. The positive message is that if these other causes of chick mortality can be reduced, well-managed wader sites are likely to be successful in producing healthy fledglings to facilitate population recovery.