Habitat use and diet selection of northward migrating waders in the Sivash (Ukraine): the use of Brine Shrimp Artemia salina in a variably saline lagoon complex

• Main Authors: Winden, Jan van der, Have, Tom M. van der, Verkuil, Yvonne, Chernichko, Iosif I
• Format: Journal Article
• Language: English
• Published: 01.01.2003

Wader species migrating through the Sivash (Ukraine) use hypersaline andbrackish lagoons. We studied the use of the two habitat types, and focusedon the profitability of Brine Shrimp Artemia salina, prey species in hypersalinelagoons for Dunlins Calidris alpina, Curlew Sandpipers Calidris ferrugineaand Broad-billed Sandpipers Limicola falcinellus (although the latterwas abundant in the brackish habitat only). Colour-marked Dunlinsrestricted feeding to the lagoon type in which they were initially captured.Dunlins and Curlew Sandpipers fed in areas where Brine Shrimps were ofaverage size (0.23-0.34 mg AFDM). Artemia intake may be restricted bythe visual foraging mode, as during rain and twilight pecking ratesdecreased to 45.9-76.8% of values measured during dry periods in full daylight.Feeding activities were higher in hypersaline than in brackish lagoon(84.6 and 69.0%, respectively). Broad-billed Sandpipers feeding onArtemia had longer handling times (0.87 s prey-1) than Dunlins and CurlewSandpipers (0.58 and 0.54 s prey-1), which performed surface tension transport(STT) of prey in their pointed, thin bills. There were no differences inbody mass increases in Dunlins in hypersaline and brackish lagoons. InBroad-billed Sandpipers, catching results suggest an increase in body massin the brackish lagoon only. Supported by intake rate-based calculations ofpotential mass gain rates, we conclude that Brine Shrimp can form a profitableprey for Dunlins and for Curlew Sandpipers, but apparently not forBroad-billed Sandpipers.