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Diet, feeding behaviour and habitat selection of breeding Eurasian Woodcock Scolopax rusticola were studied by radiotracking birds from March to July in two contrasting situations: a 171-ha lowland plantation of Sycamore Acer pseudoplatanus , Beech Fagus sylvaticus and pine Pinus sylvestris / P. nigra in Derbyshire, central England, and an area of c . 900 ha of fragmented, naturally regenerating birch Betula pendula / B. pubescens woodland and hill margin in an upland glen in Angus, northeast Scotland. Earthworms were the most important diet component of adults and chicks in terms of biomass at both sites (50-80%), the rest comprising mainly spiders, harvestmen and beetles. In spring both sexes flew c . 1 km after dusk to feed on fields at night, with up to 94% of nocturnal radiolocations on fields in March, dropping to 18% in July. This behaviour probably reflected seasonal changes in the relative availability of earthworms in fields and woodland. Diurnal home range sizes were similar at both sites and the mean size of 30-day ranges was 62 ± 20 ha (± se), although Woodcock changed locations regularly and areas used for feeding on a daily basis were typically smaller than 1 ha. In the lowland plantation, Sycamore with Dog's Mercury Mercurialis perennis ground cover was highly used relative to availability. In the upland margin study area, the same held for dense sapling-stage birch. These habitats appear to represent a compromise between food availability and protection from avian predators. Recently documented changes in the structure of British woods during the last 30 years, suggestive of reduced management and increased grazing/browsing, are likely to have been detrimental to breeding Woodcock.The Eurasian Woodcock Scolopax rusticola breeds widely throughout Britain, with notable absences only on the highest ground in parts of Scotland, and in southwest England and south Wales (Gibbons et al . 1993). Nevertheless, the species is currently 'amber-listed' as a bird of conservation concern because of an apparent long-term decline in breeding numbers (-76% during 1974-99) and range (-31% during 1968(-31% during /72-1988(-31% during /91, Gregory et al . 2002. The Woodcock is difficult to survey owing to its cryptic plumage, secretive behaviour and crepuscular displays, and hence the reliability of current population and trend estimates is questionable, but the magnitude of the estimated decline is sufficient to justify investigation of factors likely to affect Woodcock numbers.

In many colonial waterbirds, reproductive success is affected by water levels around the colonies. In a study of the Greater Flamingo (Phoenicopterus ruber roseus) in the Camargue, southern France, we examined annual variation in water levels around the breeding colony site between 1984 and 1991 in relation to (1) the number of breeding pairs, (2) colony productivity (fledglings per breeding pair), and (3) physical condition of fledglings. The number of breeding pairs each year was highly variable and was positively correlated with high water levels during the March—July period. There was no significant relationship between the number of breeding pairs and the number of chicks fledged. Although the productivity of the colony was not affected by water levels during the chick—raising period, fledglings were heavier in years with high water levels. There was no relationship between colony productivity or the absolute number of chicks fledged and the average body condition of chicks in the creche. Differences between the 1984 and 1985 cohorts in the frequency of young birds making breeding attempts (i.e., ages 5 and 6 yr) suggested that body condition at fledging may have important life history consequences. Estimation of reproductive performance in colonial waterbirds, usually limited to the average nest productivity, could be improved by considering average body condition of chicks at fledging as well.

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