Thursday, 4 May 2006

Reeling beauty

Foulden Common is a regular haunt for me during May and June. Home to a wide range of birds and insects, this mixture of short-turf grassland and scrub provides the perfect excuse for an afternoon spent wandering in search of wildlife. At the moment, there are a small number of sheep and their lambs on the common, brought in to help maintain the short turf and diversity of plants needed by resident insects, notably grizzled skipper butterfly. A visit on Sunday afternoon began in sunshine but, as the cloud thickened, the temperature dropped and few insects were on the wing. Despite the lack of invertebrates, there were plenty of birds to be seen and heard. In addition to the chiffchaffs, blackcaps, chaffinches and tits that were much in evidence, I was lucky enough to catch the reeling song of a grasshopper warbler. This grey-brown and rather anonymous looking bird has a habit of skulking low down in the vegetation; so it is fortunate that its reeling song, likened to the sound made by an angler’s reel, is so characteristic. The song, usually delivered in the evening or at night, has a rather unusual quality in that it seems to rise and fall in volume – almost as if the bird is close by and then suddenly much farther away. This effect occurs as the bird rotates its head, the volume appearing to increase when the bird is facing you.

The grasshopper warbler is a summer visitor to our region, with individuals arriving from their West African wintering grounds from the middle of April. Most birds have arrived by the beginning of May, and the male song can be heard from a range of habitats, including scrub, wetland margins, thick hedgerows and old industrial sites. The key feature of these habitats is the availability of low, dense ground cover, in which the birds can nest, coupled with some taller song posts and insect-rich feeding areas. The number of grasshopper warblers seems to fluctuate from year to year, perhaps reflecting a tendency to move between areas but, even allowing for this, this little warbler can best be described as an uncommon breeding species. The breeding season itself extends from late April through into August, potentially allowing a pair to have three nesting attempts.

The wetter margins of Foulden Common are, in many ways, ideal for the grasshopper warbler, making an evening visit to the site well worthwhile. If you need an additional reason to tempt you to the common, then the presence of nightingales should be sufficient. An evening serenade by two of our greatest songsters should be enough to tempt even the laziest of armchair birdwatchers – you don’t even need your binoculars.

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