Post-breeding season diet of the Mediterranean Gull Larus melanocephalus at the Bulgarian Black Sea coast
Atlantic seabirds , Volume 6 - Issue 2 p. 65- 78
The seeds of three cultivated plants, Barley Hordeum vulgare, wheat Triticum sp., and Sunflower Helianthus annuus, and of ragwort Senecio sp., constituted the staple diet of Mediterranean Gulls Larus melanocephalus during their post-breeding residence at the Atanasovsko Lake Reserve (in 99% of pellets, n = 2,397 pellets). Pellets with fully digested seeds of Barley, Wheat and Ragwort contained a significantly greater number of gastrolith fragments. The pellets containing only visibly undigested seeds constituted 19% of samples (n = 2,397). Of these, the seeds of seven species germinated, and five of them had germination rates over 50%. Animal remains were found in 27% of the pellets (n = 2,397) with terrestrial animals predominating. Of the invertebrate species, ground beetles in the genus Harpalus (32%, n = 1,226 individuals) and grasshoppers (24%) occurred in greatest numbers. Vertebrates consisted mainly of marine and brackish benthic fishes (76%, n = 238 individuals). The seeds and stones ingested as gastroliths came from stubble in crop fields. Gulls flew to beaches to obtain bivalve seashells as gastroliths and to forage extra food. Gulls feeding mainly in fields after the nesting season probably reflect the seasonal flush of available food in habitats suitable for feeding in the region.
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Boyan Milchev, Nikolay Kodjabashev, Yanaki Sivkov, & Dragan Chobanov. (2004). Post-breeding season diet of the Mediterranean Gull Larus melanocephalus at the Bulgarian Black Sea coast. Atlantic seabirds, 6(2), 65–78.
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