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.
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
Annie Haycock (BBS & WeBS local organiser)