Mergus serrator – HWYADEN FRONGOCH – Winter visitor
Scarce in Mathew’s (1894) time, who knew of no dated or recent records, but Lockley et al. (1949) reported that it had become a regular winter visitor to the upper Cleddau Estuary, with occasional occurrences elsewhere. It has continued to increase gradually since then, and is now regular in winter at the Teifi Estuary, Fishguard Harbour, Cleddau Estuary and off Amroth—Saundersfoot. Numbers involved are small, with probably only 40 birds present in most winters, including odd ones and twos scattered around the outer coast. The largest group recorded was 28 in Hook Reach on 31 January 1987.
Red-breasted Mergansers arrive in October and November and usually depart in March and April, but have lingered late into May on the Teifi and Cleddau and might well breed in Pembrokeshire in the future. They breed in neighbouring Ceredigion as close as the Afon Ystwyth.