Corncrake - breeding

Formerly a common and widespread breeding summer visitor to Pembrokeshire, as noted by George Owen in 1603 and Murray Mathew in 1894, the Corncrake has subsequently decreased and then disappeared as a nesting species.

The decline in the breeding population was underway by the beginning of the 20th century, accelerating after World War II when the introduction of mechanical mowers and the application of drainage and fertilisers permitted early cropping of hay, all of which resulted in low chick survival. The later widespread conversion from hay to silage further made farmland no longer suitable habitat for nesting Corncrakes.

Lockley et al. (1949) noted a decline in numbers from about 1916. B. Lloyd still found them in widespread localities in 1927, noting that at that time they were commoner in Pembrokeshire than they were in south-east England where the decline had set in earlier. By 1930 he noted that they were decreasing, only one or two being recorded each year, usually in September, with about equal frequency from the islands of Skokholm and Skomer and mainland sites such as Carreg Wasted, Llangloffan Fen and Pwllcrochan.

The decline continued, though K. J. S. Devonald could still encounter them around St Ishmaels in the late 1940’s and early 1950s, hearing them calling in the fields and becoming exposed at hay making time.

Nesting became increasingly sporadic: four or five clutches were revealed during silage cutting at Thomas Chapel in May 1962, from which the farmers reared three young that were released at Dale airfield. They were present in the breeding season at Uzmaston in 1965 and 1966 and at Pembroke in 1973. The BTO breeding bird atlas for 1968-72 noted confirmed breeding in 10Km squares SS 1090 and SN 1000, probable breeding in SN 1010 and SN 0040, with possible breeding in SN 0030 and SM 7020. No subsequent records have suggested breeding.

Stuart Devonald became fatally ill before completing the account for Corncrakes in Pembrokeshire. Graham Rees, who discussed the subject with him on many occasions, has completed the process and hopes the result will stand as a small memorial to Stuart’s input to the ornithology of Pembrokeshire.