CETTFS WARBLER - Cettia cetti

Scarce resident. Breeds. Uncommon passage migrant.

This recent colonist was first noted in the U.K. in 1961 but did not reach Cornwall until 1973. Colonisation was initially slow but by 1978 birds were reported from six localities and included the first proof of breeding at Marazion Marsh. Subsequently, breeding has been proved in most years and was probable in others. Prior to 1990 the only other site where breeding had been confirmed was at Angarrack in 1981 and 1982, but sadly the habitat was destroyed for road and industrial development, although sporadic reports from nearby Phillack may indicate a small remnant population. These successes of the early 1980's probably accounted for the continued increase and dispersal throughout the county, although some immigration may also have occurred. By 1984 birds were noted at eleven localities, whilst in 1985, despite a reduction in the number of sites, at least 36 birds were located and there was a speculative estimate of 100 birds at Marazion Marsh alone. More recently, severe winter weather caused a substantial reduction in many parts of the U.K. including a virtual eradication in the species' former stronghold in Kent. The Cornish population was apparently halved from 1985 to 1986 and was further reduced in 1987 but there has been a slight improvement annually since. In 1994 singing males were reported from the following areas (with comparative data for 1987 - 1993). Figures represent number of singing males.

The Gunwalloe count is disappointing but may result from incomplete coverage. The Halton Quay site is a new one whilst tie Perranporth total is the most there since 1977. The only other record concerned the overwintering bird at Mawgan Porth which was last noted Jan 5th. SMC.

Site fidelity since the first record in 1973 reveals that birds have been noted at Marazion in 20 years, Calstock and Gunwalloe 12 each and Par nine years.

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• Created: 5 May 2009