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The majority of Common Cranes (Grus grus) breeding in northern Europe are short- to medium-distance migrants that overwinter in southern Europe, northern Africa, and the Middle East. However, some individuals migrate longer distances to as far as Ethiopia. Using data from18 satellite-tracked juvenile Common Cranes, we assessed (1) the length and landscape composition of the migratory routes used and (2) the behaviour of neighbouring Finnish and Estonian (500 km apart in the north-south direction) sub-populations. Our results show that Common Cranes mainly use the East European flyway to reach thewintering grounds in Ethiopia, yet some individual cranesmay alternatively use the Baltic-Hungarianmigration route. Neither duration nor the number of stopovers used influenced the flight distances of the cranes. Further, 7-19 days of refuelling enabled the cranes to cover long flight distances, from 2,420 to 5,110 km in 6-15 days, without the need for settling down at potential stopovers on the route. Contrary to our expectations, the main refuelling sites of the Finnish breeding population were further south (in southern Ukraine) than those of the Estonian population (in Belarus). Despite the longer flight distances, Finnish cranes used threemainmigration stages, while cranes breeding atmore southern sites generally used mainly four stages. Our findings demonstrate that largesized social migrants such as the Common Crane may have spatially segregated, flexible migration patterns that involve only a few carefully selected stopovers during long-distance migration. [ABSTRACT FROM AUTHOR]

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, agricultural intensification or abandonment of arable land. However, there are few studies investigating the relationship between wader distribution/abundance and prey abundance. This study focused on the relationship between breeding wader abundance, habitat characteristics 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. Endogeic earthworm abundance was not significantly related to total wader abundance, although for some species there was a weak negative relationship. We conclude that epigeic earthworms are an important food source for most wader species on Matsalu grasslands and endogeic earthworms are not likely to be utilised as a prey source. Wader abundance was most strongly related to flooding as a determinate factor for breeding habitat characteristics and with epigeic earthworms as a food source. These factors are important environmental variables influencing local abundance and distribution of coastal waders. [ABSTRACT FROM AUTHOR]

The article focuses on a research that assesses the spring-arrival timing of 42 migratory bird species in Estonia from 1957 to 1996. It evaluates the divisions of migratory birds, the climatic factors that influence their spring-arrival timing, and the trends in their spring-arrival timing in connection with climate change. Results show that there are two general clusters and six sub-clusters of species during the spring arrival of migratory birds: 23 are short-distance migrants while 19 are long-distance migrants. It discusses the relationship of the short-distance migrants' first arrival dates to the seasonal winter North Atlantic Oscillation (NAO) index and other climatic variables. It adds that long-distance migrants' first arrival dates are weakly correlated with climatic factors.