EFFECTS OF RECREATIONAL DISTURBANCE ON THE FORAGING BEHAVIOR OF WADERS ON A ROCKY BEACH

Oystercatcher Haematopus ostralegus, Curlew Numenius arquata and Redsh ank Tringa tetanus reacted in a variety of ways to human disturbance. They delayed arrival and departed earlier when disturbed. Vigilance (s can rates) increased with the vigour of human activity and the birds w ere more vigilant in the higher shove zones, but there tons no corresp onding decrease in food searching (peck rates). Prey capture rates of Oystercatcher and Curlew apparently increased with moderately close hu man disturbance. Undisturbed birds may not have been foraging at maxim um rates and vested periodically during the low tide period. Character istic avoidance behaviour elicited by disturbance differed between the species; Curlew and Redshank typically stopped feeding and, if they l eft, flew away, whereas Oystercatcher walked away. This difference may be related to plumage crypsis. Flight distances of all species were v ery low. Habituation may be an important response to regular but benig n disturbance, reducing the disturbance-induced decrease in feeding ti me to a level which may be compensated for, at least in summer within the normal late-tide foraging period.