PICKING OUT THE PLUM JOBS - FEEDING ECOLOGY OF CURLEWS NUMENIUS-ARQUATA IN A BALTIC SEA WIND FLAT

On the German Baltic Sea coast most migrating shorebirds stage in wind flats that are characterized by irregular wild-induced fluctuations o f water :level. As it had been suggested that large shorebirds cannot fulfil their energetic requirements in wind flats due to the lack of p rey organisms large enough to be profitable, we investigated the feedi ng ecology of curlews Numenius arquata at Hiddensee (July to November 1995). Most prey taken were the largest ragworms Nereis diversicolor p resent in the sediment (>85 segments), while 2 bivalves contributed 4. 2% (Cerastoderma lamarcki) and 0.8% (Mya arenaria), respectively. Most curlews foraged in shallow water where we observed the maximum intake rate (3.5 prey min(-1)) compared to exposed flats (2.0 prey min(-1)). This is thought to be the result of highest surface activity and ther efore best detectability and accessibility of ragworms in shallow wate r. Prolonged periods of low foraging activity in late morning and arou nd noon as well as the aggregation at night roosts suggest that curlew s do not have problems maintaining their energy budget in the study ar ea. This is explained by their ability to find the few most profitable prey organ isms available, even though these occur at low density.