Mallard nest largely around fresh water but have shown a capability to use sites well away from water. They have also readily adapted to artificial sites, perhaps epitomised here in Pembrokeshire, by sitting on eggs aboard a working lobster–fishing boat throughout its mobile working days.
An estimate of 400 nests was made during the 1984-88 survey, though at the time this was thought to be a little conservative. Interpolation from the findings of 1988-91 National Atlas provides a figure of 460 nests for Pembrokeshire. The BBS suggests there has been a 15% decrease in population in Wales over the period 1994–2007. However, the evidence from the 2003-07 county survey is of a 27% expansion in distribution, suggesting there could have been about 500 nests by 2007. The estimates are expressed as nests rather than pairs, as male Mallards normally take no part in incubation or tending young.
Graham Rees
Fieldwork 2003-07 (based on 490 tetrads)
Red = breeding confirmed = 100
Orange = breeding probable = 57
Yellow = breeding possible = 76
Total tetrads in which registered = 233 (47.6%)