DIET, PREY-SIZE SELECTION AND INTAKE RATES OF BLACK-TAILED GODWITS LIMOSA-LIMOSA FEEDING ON MUDFLATS

This paper describes aspects of the winter feeding ecology of Black-ta iled Godwits Limosa limosa on an intertidal mudflat in the Tagus estua ry, Portugal. Their diet consisted mainly of the bivalve mollusc Scrob icularia plana, which represented 88% of the ingested biomass. The rem aining 12% was the worm Nereis diversicolor and, occasionally, the sna il Hydrobia ulvae. Ingested Scrobicularia varied between 10 and 20 mm in length, and all size classes of Nereis present in the sediment, exc ept those smaller than 20 mm, were preyed upon. A change in dietary co mposition occurred over the winter, probably in response to changes in the availability of Nereis and small Scrobicularia. Intake rates aver aged 74.9 mg dry weight per minute, which corresponded to a net energy intake of 1.21 kJ per min.