Seasonal Changes in Patch Use by a Territorial Grey Plover: Weather-Dependent Adjustments in Foraging Behaviour

Abstract

SUMMARY (1) Change in patch use from October to March by an individually marked territorial grey plover is reported. (2) On days when temperatures were > 1 ?C the bird exhibited a preference for patches where highest rates of energy intake and prey capture were achieved. Patch use was positively correlated with patch quality expressed in terms of these foraging parameters. (3) On days when temperatures were <1 ?C the preference for good patches was greater and the correlation between energy intake rate and patch use stronger. (4) Two of the four patches in which highest intake rates were achieved during cold conditions were not used under mild conditions. Two of the four patches in which intake rates were lowest during mild conditions were not used under cold conditions. (5) As a result of the pattern of selective patch use observed, rates of energy intake and prey capture were on several cold days in mid-winter (despite a general decrease in prey availability on these days) similar to intake rates on mild days. (6) The pattern of patch use described is consistent with a strategy of resource conservation during mild conditions and utilization of conserved resources during cold conditions. The implications of this hypothesis are discussed.