Circus aeruginosus – BOD Y GWERNI – Winter visitor. Not recorded from June to August
The breeding records noted by Mathew (1894) were discounted by Lockley et al. (1949) as probably referring to Montagu’s Harrier. Even in winter they were becoming scarcer by 1894. By 1949 the species was classified as a “regular but very scarce autumn and winter visitor” (Lockley et al. 1949). Saunders (1976) remarked that Hen Harriers had “increased considerably during the past twenty years”.
They usually arrive in October and November, and they depart in March and April with stragglers recorded until the end of May. They range widely across the county during the winter but are scarce south of the Cleddau Estuary and in the eastern Marches.
They hunt across most of the coastal plain, including the larger offshore islands, as far east as the Preseli Mountains. The males tend to use the agricultural areas more than the females. Roosts have been located at Plumston, Puncheston, Pantmaenog, Mullock Bridge, Marloes Mere and Dowrog—Tretio. Most roosts contain two or three birds but Dowrog—Tretio usually attracts between six and eight and up to 14 have been seen gathering there. Distinctively marked Hen Harriers occur some years and tracing their movements has shown that birds roosting at Dowrog—Tretio can range as far afield as Martin’s Haven. It is not known whether there is any interchange of individuals between roosts.
SAUNDERS, D.R. 1976. A brief guide to the birds of Pembrokeshire. Five Arches Press