2008 Vol 21.1

MEDITERRANEAN GULLS COLOUR-RINGED IN THE NETHERLANDS AND BELGIUM AS SEABIRDS IN PORTUGAL
Poot M. & R. Flarnant 2008. In Nederland en Belgie gekleurringde Zwartkoprneeuwen Larus inelanocephalus als zeevogel in Portugal. Sula 21(1): 33-35. Several thousands Mediterranean Gulls Larus rnelanocephalus were observed in the winters of 2004/2005 and 2005/2006 at two sites along the west coast of Southern Portugal. Along the Lisbon coast (Guincho-Cascais-Estoril-Parede, west of Lisbon) a maximum of 6000 birds was observed and along the Alentejo coast at least 1000 birds were present in the Mira river mouth, near Vila Nova de Milfontes. With an unknown, but probably considerable number of birds wintering along the Algarve coast, the total number of birds wintering in Portugal south of Cabo da Roca is estimated at a minimum of 7000-8000 birds. This estimate is six times higher than the previous estimate in the nineties of 1200 wintering birds. This increase is likely explained by the increase of the breeding population in Western and Central Europe. Behavioural observations suggest that along the Lisbon coast the birds mainly feed offshore. Sightings of colour ringed birds indicate that birds came from Belgium, the Netherlands and France with a small proportion coming from other countries. The low rate of re-sightings of individual colour-ring birds suggests that a very high number of ringed birds wintering in Portugal remained unnoticed so far. The Portuguese coast south of Cabo da Roca is clearly the most important currently known wintering site along the European and North-African Atlantic coast, and the data gathered from colour-ring readings highlight the importance of this area as a wintering ground for the Mediterranean Gulls breeding in The Netherlands and Belgium.

2008 Vol 21.1

FIRST ROOF-NESTING LESSER BLACK-BACKED GULLS IN UTRECHT IN 2007 AND 2008
Poot M. 2008. De eerste Kleine Mantelmeeuwen Larus fuscus broedend op een dak in Utrecht in 2007 en 2008. Sula 21(1): 36-37. 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. Nesting 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.