Gadwall – 2021 Winter

Mareca strepera – HWYADEN LWYD – Winter visitor, has bred

The gadwall has been increasing in numbers and distribution in winter since the 1960s.  However, there was a lack of birds in Pembrokeshire (and in Wales) during the early-mid 1990s, and again in 2007-08.  Recent winters have again shown a decline in numbers.  The reason for this is not clear, although as this is primarily a freshwater species, it is possible that its occurrence in this part of the country may depend on whether lakes further north are frozen over or otherwise unaccessible.

Gadwall are kleptoparasitic on species such as coot and swans that feed on submerged vegetation – bringing it to the surface where the gadwalls can reach it.  It is therefore possible that the recent decline in gadwall here is related to the decline in coot since 2010. 


This map was produced by the West Wales Biodiversity Information Centre using data collected between November and February for the BTO Atlas 2007-11, with additional data collected in 2011-12 winter to fill gaps in coverage.

The main sites are:

  • Bosherston Lakes (5-year maximum average = 11)
  • Marloes Mere (5-year maximum average = 16)
  • South Hook Pools (5-year maximum average = 23)

Wetland Bird Survey

Monthly counts for the current season can be found here

Pattern of occurrence

The number of records each week since 2000 from BirdTrack. This gives an idea of when they are most likely to be seen.  Most records do not include counts. May-June records generally refer to single birds, however up to six were present at Marloes Mere in June 2014, and a male was apparently keeping company with a female mallard and her chicks on Pembroke Millpond 2011.

Annie Haycock (BBS & WeBS local organiser)

More about the Gadwall in Pembrokeshire