Grey Heron - 1994

Breeding resident

Heronry sites have shifted widely during recorded times, that at Slebech Park being the only one that has been consistently occupied since Mathew (1894). Total numbers vary, with very cold winters causing increased mortality when ice renders prey inaccessible. The breeding population varies between about 30 pairs when at a low ebb (e.g. in1962) and 65 pairs in more favourable times (e.g. in 1974). However, some colonies declined in the late 1980s despite mild winters and against the national trend. Single pairs occasionally nest away from established colonies and can then be easily overlooked. Colonies vary between five and twenty nests. That at Slebech has contained as many as 46 nests but has decreased in recent years (see Table 4). Herons formerly bred on the cliffs in the Solva—Newgale—Nolton areas of St Bride's Bay and at Linney Head, but this has not been recorded since 1974. A pair nested on the ground at Trefeiddan in 1978.

Grey Herons feed widely across the county, from the outer coast to the smallest inland pool, even exploiting the upper slopes of the Preseli Mountains at frog-spawning time. They disperse widely in the autumn, birds reaching all the offshore islands and on several occasions small parties of juveniles have been seen flying due west out to sea.

Fieldwork 1984-88 (based on 478 tetrads)

Red = breeding confirmed = 10

Total tetrads in which registered = 10 (2.1%)

Donovan J.W. & Rees G.H (1994), Birds of Pembrokeshire