Prey Detection by Intertidally Feeding Lapwing

and Summary Observations on lapwing foraging on estuarine mudflats showed that:1 They detected prey during stationary scanning pauses. 2 The majority of prey items were taken within three paces of the scanning position; the polychaete Nereis diversicolor was taken at greater distances than the amphipod Corophium volutator . 3 Pecks that proved abortive occurred after a greater number of paces than successful pecks, and their proportionate incidence increased with distance from the pause position; it is argued that aborted pecks are due to misidentification of prey cues rather than escape of the prey. 4 After failing to detect prey from one position, birds gave up and moved to a new scanning position; the median distance moved corresponded to the radius of an area within which 99% of prey items were located. 5 The total distance moved while taking prey (including steps taken after capture but before the next scanning pause) rarely took birds beyond the boundary of the previously scanned area; birds that chose to remain in the previous scanning position had higher subsequent probabilities of taking prey than those that moved to scan a fresh area. 6 There was a negative correlation between success rate (proportion of pauses that resulted in prey capture) and rate of movement (steps per min); this was caused by increased distances moved between pauses in low quality foraging areas, and not by handling times interfering with searching, as there was a positive correlation between the number of prey handled per min and searching rate (number of pauses per min).