Anas platyrhynchos – HWYADEN WYLLT – Breeding resident, passage migrant and winter visitor
|No of tetrads occupied||183 (of 478)|
|Percentage of tetrads||38.3%|
This is the bird that Mathew (1894) knew as the Wild Duck, and it has probably not changed its status to any degree over the past 100 years or so. Lockley et al. (1949) described it as a common resident and winter visitor.
The Mallard breeds throughout Pembrokeshire, in a range of habitats including the islands. A breeding population of some 400 nests may well be an underestimate as the birds are inconspicuous until the broods are out and then not always seen. The total post-breeding population is augmented by reared birds released by wildfowlers, numbers of releases varying from year to year. The Mallard remains widespread outside the breeding season but groups of 100-500 concentrate at favoured localities, such as the Cleddau Estuary, Pembroke Mill Ponds, Bosherston Pools, Pentood Marshes, Marloes Mere, Nevem Estuary and less regularly at other spots. Shifts in distribution are frequent and often sudden, making this a difficult species to assess. Cross breeds with domestic ducks are not infrequent and pure white birds seem to occur naturally among otherwise normal broods. Keeping track of some of these distinctively marked birds illustrates their mobility between localities. Up to 1,500 Mallards normally winter in the county with an exceptional gathering of about 1,500 on Skomer on 23 October 1981, which probably included passage migrants. Peak numbers occur between October and January.
There are fewer recoveries of Mallards ringed at Orielton than for Wigeon or Teal (see above); those which there are mostly relate to passage periods but a breeding season return came from Korelia in north-west Russia. They pass on through the county to Ireland and France and do not necessarily return to Pembrokeshire in the years after ringing, when they occur in other parts of Wales and in England. There is little evidence of diurnal migration.