waders and their estuarine food supplies - Vlaams Instituut voor de ...

INTRODUCTION
Ms,i invest 409 of (heir soli bod) in ilieir siphon. This allows them to filter I.MH.1 boas the water and nonetheless live deep") buried.
does not take specimens larger than observed.
Why do Oystercatchers and Curlews ignore the
smaller specimens'.' The optimal diet model gives the
explanation. Assuming thai Oystercatchers maximize
their intake rate during feeding, the) have to ignore
smaller than 17 mm. For the Curlews, the lower
acceptance levd was calculated to be' 25 mm. Both
bird species would only lower their intake rale were
these small pre) included in their diet. Birds appear to
obey litis profitability rule.
Concluding, the profitable, ingestible and accessible
fractions Of Mya may be defined lor each predai. C
19
These fractions differ between predators. This explains
the fiming of predation pressure bj the three
bird species and the resource partilioning among these
predators. The clams have to traverse several windi iw s
of predalion during the first four years of their life, but
every time they can only survive when the) bury
deeply and. thus, have a long siphon.