Birdwatch: Warbling tune in Yorkshire woods

A wood warbler.
A wood warbler.
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I hear from quite a few readers of this column but one of the more unusual is a captain who quite often e-mails me photographs of birds that have hitched a lift on his ship.

The last one was of this wood warbler which rested on one of the ship’s rails for a while in the middle of the Irish Sea before continuing its journey - hopefully to nest in a Welsh or English woodland somewhere.

The wood warbler’s song is a strange one, compared to a coin spinning on a marble slab and delivered in two stages, first a soft whistle, then a series of quickening notes growing in volume and repeated every few minutes.

Wood warblers are very localized in Yorkshire, preferring stands of oak and beech trees where the pale yellow throat and white underparts blend in with the fresh green leaves.

The wood warbler is the largest of our three “leaf warblers”, the others being the chiffchaff and willow warbler, and is the most aptly named.

Oak or beech trees usually have little or no undergrowth beneath them or lower branches, so the wood warbler has to take the rather risky option of ground nesting, building a domed nest from grass in the leaf mould.

Wood warblers are declining in many countries across their breeding range including the UK, where there’s been a 69 per cent drop since the 1990s. Even in their remaining strongholds, the best known in Yorkshire being the Strid Woods at Bolton Abbey, numbers are significantly lower.

The reasons are still unclear, the problems might occur on breeding or wintering sites, on migration, or a combination of all three. Studies carried out by the RSPB have shown the wood warbler’s exposed nests are predated by many species but especially jays while the chicks are vulnerable to starvation in prolonged spells of wet weather.

Wood warblers are on their way back to Africa by mid-September and are unusual in that they fly south west to northern Italy where they feed and put on weight for several weeks before they continue south across the central Sahara to the as yet unidentified wintering grounds.

For the third year running a male little bittern has returned to Old Moor reserve near Barnsley. This summer visitor to Europe from Africa was first confirmed to have bred in this country in 1983 when a pair reared three young on the Potteric Carr reserve, Doncaster and they have now begun to become established in Somerset. So far the Old Moor male has failed to find a female.

Wood, green and common sandpipers, ringed plovers, curlews and black-tailed godwits were seen across the region this week, while spotted redshanks were among the waders at Blacktoft Sands. There were more honey buzzard sightings at the Wykeham forest viewpoint, North Yorkshire and a first summer Sabine’s gull was on Flask Lake at the Nosterfield Quarry reserve, North Yorkshire. Up to five little gulls were on Hornsea Mere and one at Skelton Lake, Leeds.