K. Hulsman et al., SEARCHING BEHAVIOR AND DIET OF OYSTERCATCHER HAEMATOPUS-OSTRALEGUS PAIRS FEEDING IN THEIR TERRITORIES, Ardea, 84A, 1996, pp. 131-139
Search path, searching behaviour and diet of pairs of Oystercatchers f
eeding in mudflat territories were studied during spring. females ate
Nereis, Mya, small unidentified prey, probably Corophium, and a few Ma
coma, whereas males primarily ate Macoma. Even when female and male fo
raged in the same site, they often caught different prey. The combinat
ion of 'The Search-rate/Detection Model' (Gendron & Staddon 1983) and
'The Harvestable Prey Model' (Zwarts & Wanink 1993) provide the theore
tical framework in which to explain these differences in diet. Macoma
are thought to be more cryptic than Nereis, Mya and Corophium. Therefo
re females, while searching at a faster rate than their respective mat
es, caught far fewer cryptic prey, but a greater number of more conspi
cuous prey than their mates. On the basis of distances moved before an
d after capturing prey, males exhibited area-restricted searching for
Macoma and Corophium. In contrast, females did not exhibit any area-re
stricted searching. it is suggested that the distribution of Macoma an
d Corophium available to males searching slowly was more clumped than
that of these two prey species available to females searching more qui
ckly.