Factors affecting the flight altitude of migrating waterbirds in Western Estonia

The article examines the effects of weather, temporal factors and distance to coast on the flight altitude of migrating waterbirds in Western Estonia. A laser range finder and marine surveillance radar were used to measure flight altitudes. Visible effects on avian flight altitude due to weather conditions such as wind conditions, visibility and cloud cover were identified. Tailwinds were found to be associated with elevated flight altitude, while reductions in altitude were reportedly due to high wind speed. It was noted that behavioural and physical adaptations to the environment also helped in specific flight altitude selection

Coastal grassland wader abundance in relation to breeding habitat characteristics in Matsalu Bay, Estonia

Wader populations have been declining worldwide, providing a fundamental question as to which environmental factors limit population growth. Many studies have focused on the effects of habitat change on wader populations as a result of climate change, agricul-tural intensification or abandonment of arable land. However, there are few studies inves-tigating the relationship between wader distribution/abundance and prey abundance. This study focused on the relationship between breeding wader abundance, habitat character-istics and prey abundance on different types of coastal and floodplain grasslands. The study was carried out in the Matsalu Bay area, Western Estonia between 2001 and 2005. Results showed that most wader species were strongly related to habitat flooding type but not to plant species richness or evenness or mean vegetation coverage. Abundance of epigeic earthworms at a site was positively correlated with wader species diversity and abundance, as well as at the individual species level for abundance of Northern Lapwing Vanellus vanellus, Black-tailed Godwit Limosa limosa and Redshank Tringa totanus

Waterbird Populations and Pressures in the Baltic Sea

This report outlines the results of the internationally coordinated census of wintering waterbirds in the Baltic Sea 2007-2009 undertaken under the SOWBAS project (Status of wintering Waterbird populations in the Baltic Sea). The estimated total number of wintering waterbirds was 4.41 million compared to 7.44 million during the last co-ordinated census 1992-1993.  Despite the general declines stable or increasing populations of herbivorous species were recorded. While benthic carnivores with a coastal distribution have either shown moderate declines, stable or increasing populations seaducks with an offshore distribution have declined seriously. Based on analyses of trends in wintering waterbirds and pressures indicators are suggested as performance indicators in relation to the international and national actions taken to reduce the anthropogenic pressures in the Baltic Sea