1. Dept of Marine Ecology; NIOZ Royal Netherlands Inst. for Sea Research; PO Box 59, NL-1790 AB, Den Burg, Texel the Netherlands
2. Dept of Vertebrate Zoology; Biological Faculty, Lomonosov Moscow State Univ.; RU-119991 Moscow Russia
3. Dept of Ecology and Evolutionary Biology; Cornell Univ.; Corson Hall, Ithaca NY 14850 USA
4. Chair in Global Flyway Ecology, Animal Ecology Group, GELIFES, Univ. of Groningen; PO Box 11103, NL-9700 CC Groningen the Netherlands