HUSTINGS F (2005) Breeding success of European Reed Warblers Acrocephalus scirpaceus in the capricious summer of 2004. LIMOSA 78 (1): 39-42.

The breeding biology of a small population of European Reed Warblers was studied in 2004 during weekly visits at a sand and gravel pit in the province of Limburg, Southeastern Netherlands. In 73 nests, egg-laying was started between 20 May and 1 August (fig. 1). After a period with more or less normal weather, weather conditions seriously deteriorated from mid June onwards, with a series of depressions accompanied by heavy rains (except for the end of July/beginning of August) and storms around 23-24 June and 17 July. Due to these circumstances, local reedbeds (4.2 ha distributed along a 1800 m bank) became severely damaged (39% of surface unsuitable to nesting and 44% moderately damaged on 14 July, situation seriously deteriorating afterwards). Nest success (calculated according to Mayfield and defined as the percentage of nests with fledged young) before and after 22 June differed markedly (49% and 31%, respectively) but overall success (38%) was only slightly lower than recorded during a comparable study under much better weather conditions in a nearby area (Ooijpolder, distance 11 km, 147 nests) in 1995-97 (44%). This was partly caused by the preference that nesting birds showed for narrow strips of reed (less damaged than larger reedbeds) and the persistency with which nesting birds continued their breeding attempts, even in damaged reed. However, partial losses of eggs and young must have had a depressing effect on the total reproductive output, and survival of fledglings in the damaged reedbeds may have been low. European Reed Warbler Acrocephalus scirpaceus

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