The Effects of Environmental Conditions on Feeding Rates and Prey-Selection of Shore Plovers

The effects of environmental conditions on the feeding rates of Ringed and Grey Plovers, Charadrius hiaticula and Pluvialis squatarola, were investigated on intertidal sand-flats at Lindisfarne National Nature Reserve, Northumberland, England. The rate of taking large prey increased with environmental conditions in which these prey became more active, or detectable, at the sand surface, notably warmer temperatures, lower wind-force and wet substrate (the last manifested as short times after tidal exposure). When the rate of taking large prey was low, the rate of taking smaller prey increased with environmental conditions in which these prey became more active, or detectable, at the sand surface. As larger prey became more available, however, these were selected and feeding rates on small prey fell. The potential influences of some environmental factors on feeding rate where manifested only when other environmental factors were adverse.