Garrulus glandarius – YSGRECH Y COED – Breeding resident
|No of tetrads occupied||200 (of 478)|
|Percentage of tetrads||41.8%|
Resident according to Mathew (1894) and Lockley et al. (1949) but not numerous. Today, Jays breed throughout the wooded areas of Pembrokeshire including the more mature conifer plantations. Experience of some woodland plots suggests that three pairs per tetrad would be a reasonable assessment of average density, and hence the total population would be about 600 pairs.
They are periodically eruptive, with small groups being found wandering around the open coast during the autumn. This could be triggered by high productivity or a response to food shortage. The acorn crop failed in 1983 and Jays were widely eruptive in both Britain and on the continent. They had enjoyed a successful breeding season in West Wales that year, and the combination of these factors resulted in many flocks wandering westwards, largely in October and early November (John and Roskell 1985). In 1983, 200 birds passed south over Martin’s Haven on 6 October and 127 coasted southwards at Strumble Head on 19 October. Many smaller parties were seen moving along all the coasts and groups of up to 20 were frequently seen about the exposed coastal plains, where Jays are not normally found. Up to 38 reached Skomer and two were seen flying out to sea towards Ireland from Strumble Head — they were watched until lost to view, still heading steadily north-west.
JOHN, A.W.G., and ROSKELL, J. 1985. Jay movements in autumn 1983. British Birds 78: 611—637.