Action: Provide supplementary food for waders to increase reproductive success
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A small controlled trial from the Netherlands found that Eurasian oystercatchers Haematopus ostralegus did not produce larger replacement eggs if provided with supplementary food, and their eggs were, in fact smaller than the first clutch, whereas control females laid larger replacement eggs.
Supporting evidence from individual studies
A small controlled trial on a saltmarsh on the island of Schiermonnikoog, The Netherlands (Jager et al. 2000) found that seven female Eurasian oystercatchers Haematopus ostralegus, following the experimental removal of their first clutch, did not produce significantly larger eggs (as part of a replacement clutch) if provided with 50 boiled mussels Mytilus edulis (averaging 46 mm long) a day, compared with control (unfed) oystercatchers (average egg volume of 41.2 cm3 for fed females, n = 7 vs. 43.4 cm3 for control females, n = 19). In addition, the replacement eggs of fed females were, on average, smaller than original eggs (by 0.9 cm3), whereas replacement eggs for control females were larger than originals (by 0.2 cm3).