De eerste Kleine Mantelmeeuwen Larus fuscus broedend op een dak in Utrecht in 2007 en 2008

Common Terns Sterna hirundo were known to have colonised a large industrial site in Utrecht city some years ago, nesting on a flat roof top. The Common Tern colony on the roof is already present since the early nineties. Local enrichments on the roof caused by the defecating terns stimulated the growth of mosses and more substantial vegetation in recent years. esting attempts of gulls seemed a matter of time only. Lesser Black-backed Gulls Larus fuscus were first found prospecting this inland roof-top site in 2006 and a serious nesting attempt occurred in 2007. At least two pairs produced fledglings in 2008.