CAMPHUYSEN CJ, CAMPHUIJSEN DC & SPANJE TM VAN (2005) Diet of Lesser Black-backed Gulls Larus graellsii in a Dutch inland colony. LIMOSA 78 (4): 145-154.

Lesser Black-backed Gulls are coastal breeding birds that established a breeding population in The Netherlands around 1926. After a slow start the population increased markedly to around 90 000 pairs in 2002. Most breeding colonies are situated in coastal dunes and industrial estates, but in recent years, most colonies in dunes along the mainland coast have been deserted, mainly as a result of depredation by Red Fox. In search for alternative breeding sites, increasing numbers breed some distance away from the coast. The colony with c. 120 breeding pairs in 2005 at Wormer- and Jisperveld, a peat meadow area some 16 km from the North Sea coast (52°31'N, 4°50'E, 1-2 m below sea level), is an example of a recent attempt to breed further inland. Coastal Lesser Black-backed Gulls are known to raise chicks on a marine diet dominated by fatty fish such as clupeids captured well offshore, supplemented by discards obtained at trawlers. There is insufficient knowledge of the diet of inland feeding Lesser Blackbacked Gulls, and even less of the diet of birds nesting away from the coast. We studied the diet of Lesser Black-backed Gulls in the Jisperveld colony on the basis of prey remains found alongside nests, within discrete territories. Of 161 samples taken, 36 pellets contained just hair or grass leaves. In the remaining 125 samples, 196 individual prey items were found (1.58 per nest). Animal prey (121 samples) included fish (18.9%), mammals (34.7%), birds (23.0%), crustaceans (11.2%), insects (3.1%) and litter (9.2%; Figure 1). Insects and other soft-bodied prey were probably largely overlooked; this fraction should be assessed more accurately in later studies. Fish included both marine species (Scad, Whiting, Dab) and freshwater fish (Carp, Silver Bream, Roach, Rudd). Mammalian prey included Brown Hare, Mole, Water Vole, Common Vole, Root Vole, and Common Shrew. Bird prey included downy young of meadowbirds (Blacktailed Godwit, Common Redshank, Northern Lapwing), chicks of waterfowl (Mallard, Tufted Duck, Water Rail). Two adult Mallards and two nearly fully grown Brown Hares were probably taken while scavenging roadkills or other carcasses. All Crustaceans were Common Swimming Crabs. In all, 15.2% of all prey were of marine origin, 9.2% were human litter, while the rest could have been picked up in the immediate vicinity of the breeding colony. Some gull pairs were specialised feeders, with one producing 55.6% of all litter prey found, two pairs producing 72.7% of the crustaceans, and two more pairs 16.2% of the fish (of which 37.5% were marine). Several of the specialist birds must have been long-distance feeders and a future study may shed light on the differences in reproductive success between longdistance prey-specialists and more opportunistic birds that feed in the vicinity of the colony . Lesser Black-backed Gull Larus fuscus

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