Seasonal changes in the response of oystercatchers Haematopus ostralegus to human disturbance


  • Richard A. Stillman,

  • John D. Goss-Custard

R. A. Stillman (correspondence) and J. D. Goss-Custard, Centre for Ecology and Hydrology (CEH) Dorset, Winfrith Technology Centre, Winfrith Newburgh, Dorchester, Dorset DT2 8ZD, UK. E-mail:


The response of foraging animals to human disturbance can be considered as a trade-off between the increased perceived predation risk of tolerating disturbance and the increased starvation risk of not feeding and avoiding disturbance. We show how the response of overwintering oystercatchers Haematopus ostralegus to disturbance is related to their starvation risk of avoiding disturbance. As winter progresses, oystercatcher energy requirements increase and their feeding conditions deteriorate. To survive they spend longer feeding and so have less spare time in which to compensate for disturbance. Later in winter, birds approach a disturbance source more closely and return more quickly after a disturbance. Their behavioural response to disturbance is less when they are having more difficulty surviving and hence their starvation risk of avoiding disturbance is greater. These results have implications for studies which assume that a larger behavioural response means that a species is more vulnerable to disturbance. The opposite may be true. To more fully understand the impact of disturbance, studies should measure both behavioural responses and the ease with which animals are meeting their requirements. Conservation effort should be directed towards species which need to spend a high proportion of their time feeding, but still have a large response to disturbance.