Human disturbance of breedingWood Sandpipers Tringa glareola: implications for "alert distances" in prescribing protective buffer zones

Separation of animals and humans using a protective set-back distance (Minimum Approaching Distance) is a popular tool for conservation managers to promote wildlife-human coexistence. In several cases,Minimum Approaching Distance is based on how animals respond to an approaching human, using Flight Initiation Distance or Alert Distance. Alert Distance, when animals first show increased vigilance to an approaching human, is considered the best basis for Minimum Approaching Distance because animals have time to adapt their response. Alert Distance is frequently difficult or impossible to measure in practice, however, especially in breeding birds. Using a study of breeding Wood Sandpipers Tringa glareola, in which Alert Distance could not be measured directly, we tested three possible solutions to this dilemma. This suggests that, this rule may have general utility in predicting Alert Distance when only the more readily measured Flight Initiation Distance metric is known. A Minimum Approaching Distance of 160 m is recommended for breeding Wood Sandpipers.