Whooper swan cygnus cygnus January population censuses for northwest mainland Europe, 1995-2015

Research output: Contribution to journalArticle

Abstract

Internationally coordinated censuses of Whooper Swans Cygnus cygnus across continental northwest Europe were undertaken in mid-winter 1995, 2000, 2005, 2010 and 2015. The estimate of 138,500 birds in 2015, the highest to date, represented a more than doubling of the population size (at an annual increase of 4.1%) since the first census total of 59,000 swans in 1995. The largest increase was in Denmark, where numbers almost trebled from 21,740 in 1995 to 62,620 in 2015. More than 97% of all swans were counted in just six countries. The percentage of total numbers increased significantly between 1995 and 2015 in Denmark (from 36.5% to 45.2%) and Germany (26.0% to 34.7%), but declined significantly in Sweden (14.2% to 8.4%), Norway (13.1% to 3.6%), Poland (6.2% to 4.0%) and the Netherlands (2.4% to 1.7%). The counts show an increasing discrepancy between national trends in abundance for Whooper Swans in Sweden and especially in Denmark in comparison with results obtained only from mid-winter International Waterbird Count (IWC) site coverage. This demonstrates the increasing tendency for Whooper Swans to winter in areas away from traditionally counted IWC sites and confirms the continued need for a regular cycle of coordinated dedicated swan counts to anchor population trends generated from other data sources.

Details

Authors
  • Bjarke Laubek
  • Preben Clausen
  • Johannes Wahl
  • Maria Wieloch
  • Włodzimierz Meissner
  • Paul Shimmings
  • Bjørn Harald Larsen
  • Menno Hornman
  • Tom Langendoen
  • Aleksi Lehikoinen
  • Leho Luigujõe
  • Antra Stīpniece
  • Saulius Švažas
  • Laimonas Sniauksta
  • Verena Keller
  • Clémence Gaudard
  • Koen Devos
  • Zuzana Musilová
  • Norbert Teufelbauer
  • Eileen C. Rees
  • Anthony D. Fox
Organisations
External organisations
  • Aarhus University
  • Federation of German Avifaunists (DDA)
  • University of Gdansk
  • Norwegian Ornithological Society/BirdLife Norway
  • Dutch Centre for Field Ornithology
  • Wetlands International
  • Finnish Museum of Natural History
  • Estonian University of Life Sciences - EMÜ
  • University of Latvia
  • The Swiss Ornithological Institute
  • Research Institute for Nature and Forest
  • Czech University of Life Sciences Prague
  • BirdLife Österreich
  • Wildfowl & Wetlands Trust
  • No affiliation available (private)
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Ecology

Keywords

  • Census, Distribution, Mainland Europe, Population size, Whooper Swan
Original languageEnglish
Pages (from-to)103-122
Number of pages20
JournalWildfowl
Issue number69
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes