Focus

      Unexpected breeders

      bild

      Common Eider © Marcel Burkhardt

      The distribution of breeding birds is in constant flux. Occasionally, birds that normally breed far from Switzerland will temporarily or permanently settle in central Europe – a dynamic that never fails to surprise and fascinate birdwatchers and scientists alike.

      Located at the heart of Europe and at the intersection of several biogeographical regions, Switzerland has a remarkably high species richness. This is especially true for ducks, some of which spend the summer here after wintering in Switzerland, or even breed here. Often, these species reach the periphery of their breeding range in Switzerland – Common Teal, Garganey, Northern Shoveler and Ferruginous Duck, for example. Such events are more spectacular when they involve typical maritime species. The Common Eider, a characteristic bird of northern European coasts, significantly increased its wintering population in Switzerland in the 1970s and 1980s. After several influxes, small groups began to spend the summer here. Breeding was confirmed for the first time in 1988 and occurred almost every year from 1992 onwards, albeit in small numbers, a situation that is unique in central Europe.

      Distribution map for the Common Eider: Switzerland lies far from the species’ habitual breeding and wintering grounds. Nevertheless, the Common Eider is a regular passage migrant and winter visitor, and has bred here almost every year since 1992.

      © Background map: Natural Earth, Stamen Design & OpenStreetMap

      Red-breasted Merganser and Arctic Tern are also native to the north. Nevertheless, they have bred irregularly in the Fanel nature reserve BE/NE since 1993 and 2014, respectively. For both species, it is their southernmost breeding site. A mixed pair of Arctic and Common Tern bred in the Rhine delta A in 2010–2013. The Common Shelduck first bred in Switzerland in 1998 and has regularly bred on Lake Geneva since 2011, far away from the nearest larger populations.

      Distribution map for the Red-breasted Merganser: Red-breasted Mergansers normally occur on the coasts of northern Europe. Lake Neuchâtel is the species’ southernmost breeding site in central Europe.

      © Background map: Natural Earth, Stamen Design & OpenStreetMap

      Besides species that established themselves for longer periods, isolated cases of breeding occurred by birds whose colonisation process is known to be quite dynamic. Among them are Greater Short-toed Lark, Citrine Wagtail, Black-winged Stilt and Greenish Warbler. Some have only bred in Switzerland once, but others may attempt to breed again in the near future. Finally, Eurasian Dotterel and Red-spotted Bluethroat are special cases, forming small breeding populations in the central and eastern Alps, far from the northern European tundra.

      It is hardly possible to find a common denominator to explain the presence in Switzerland of species with such different population dynamics. But these cases illustrate that individual pioneers, possibly responding to environmental changes, play an important role in the colonisation of a region. Such events have certainly always occurred, but they are now easier to detect and investigate thanks to the increased popularity of field ornithology, improved tools to identify birds, and the much faster dissemination of reports. Birdwatchers can look forward to more thrilling surprises in the years to come.

       

      Text: Jérémy Savioz


      Recommended citation of the Atlas online:
      Knaus, P., S. Antoniazza, S. Wechsler, J. Guélat, M. Kéry, N. Strebel & T. Sattler (2018): Swiss Breeding Bird Atlas 2013–2016. Distribution and population trends of birds in Switzerland and Liechtenstein. Swiss Ornithological Institute, Sempach.

      References

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      Cereda, A. & B. Posse (2002): Habitats et reproduction de la Gorgebleue à miroir roux Luscinia svecica svecica au Tessin (Alpes suisses). Réflexions sur le statut de la sous-espèce en Europe moyenne. Nos Oiseaux 49: 215–228.

      Curchod, J., G. Carron, L. Maumary & B. Posse (1990): Première preuve de nidification de l'Alouette calandrelle, Calandrella brachydactyla, en Suisse. Nos Oiseaux 40: 345–353.

      Glutz von Blotzheim, U. N. (1997): Erste Brut der Zitronenstelze Motacilla citreola in der Schweiz und aktueller Stand der Arealexpansion. Ornithol. Beob. 94: 347–352.

      Knaus, P. (2000): Die Brandgans Tadorna tadorna als neuer Brutvogel in der Schweiz. Ornithol. Beob. 97: 7–20.

      Maumary, L. & F. Schneider (2018): Première preuve de nidification du Pouillot verdâtre Phylloscopus trochiloides en Suisse. Nos Oiseaux 65: 35-52.

      Monnier, B. (1995): Considérations sur les premières nidifications du Harle huppé (Mergus serrator) en Suisse en 1993 et 1994. Nos Oiseaux 43: 139–153.

      Müller, C. (2015): Seltene und bemerkenswerte Brutvögel 2014 in der Schweiz. Ornithol. Beob. 112: 189–202.

      Müller, C. & B. Volet (2014): Seltene und bemerkenswerte Brut- und Gastvögel und andere ornithologische Ereignisse 2013 in der Schweiz. Ornithol. Beob. 111: 293–312.

      Müller-Derungs, M., R. Lentner, E. Albegger & P. Knaus (2014): Neue Brutnachweise des Mornellregenpfeifers Charadrius morinellus in Graubünden. Ornithol. Beob. 111: 1–12.

       

      Subject
      Waters and wetlands
      Distribution of birds (biogeography)
      New breeding species
      Species on the rise
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