Population size, population development and habitat use by Avocets in Western Europe at the end of the 20th century
57 – 112
1 August 05
Hermann Hötker, Rodney West
Michael-Otto-Institut im NABU, Goosstroot 1, 24861 Bergenhusen, Germany.
The population of Avocets in western Europe experienced a very extensive variation during the 20th century. At the end of the 1990s, 29,496 Avocet pairs were counted in western Europe (Estonia, Lithuania,Sweden, Denmark, Germany, the Netherlands, Belgium, United Kingdom, France, Spain, Portugal, Italy, and Austria). The largest populations occurred in the Wadden Sea and in Spain. In the north-eastern part of their European range Avocets mainly nested on salt marshes. On the coast of the Atlantic and the Mediterranean Sea salt pans formed the most important habitat. The population development of Avocets followed three distinct geographical patterns. Numbers of Avocets breeding in Austria, the Mediterranean coast of France and Portugal remained relatively stable during the second half of the 20th century. In all other countries the population was very low at the beginning of the 20th century and increased from as early as 1940 onwards. In the Wadden Sea and the Dutch-Belgian delta region the increase halted in the late 1980s and then turned into a slight but significant decrease thereafter. In Estonia, Lithuania, Sweden, the UK, France (Atlantic coast), Spain and Italy numbers of breeding Avocets were still increasing during the 1990s. In total, the western European Avocet population was stable in the 1990s. Most western European Avocets now live in reserves, both within and outside the breeding season. Potential threats to the population include loss of habitats (change of use or abandonment of salt pans, sea level rise), change of weather during the breeding season (reduced breeding success), and environmental disasters like oil spills outside the breeding season, when the population concentrates in relatively few sites.