This is Michael Walter's latest report:
One of the delights of my early morning spring bird surveys is the frisson when the unexpected turns up. Most of these weekly visits can produce a record that is a little different, usually along the lines of a nightingale in a new territory, but occasionally something totally unpredictable presents itself. Two weeks ago I was surveying a fairly quiet area. At such times I have to admit to operating on autopilot, but a sudden, rapidly repeated, staccato note caused me to instantly switch to manual, realising that I was listening to a wood warbler, a bird I hadn’t recorded on the reserve since 1998. Curiously, prior to that, I had records of this summer visitor every year since my arrival in 1982, and in some years one or more pairs stayed to nest. That last bald statement is actually rather more intriguing than it sounds. The wood warbler has a markedly western distribution in the UK, breeding mainly in the West Country, Wales and western Scotland, its only stronghold in southern England being the New Forest, and it has always been a distinct rarity in Kent. Unlike the other warblers that breed at Blean, the wood warbler shuns scrub, preferring mature woodland with little or no ground vegetation, and the dead-leaf carpet beneath patches of beechwood here had proved attractive to the occasional pair in the past. Unfortunately, the recent BTO atlas demonstrated conclusively that this lovely little bird is disappearing throughout its UK range, with a massive 65% decline between 1995 and 2010, so its last appearance at Blean in 1998 fits neatly into this sad tale of loss. Research so far suggests that the cause may lie with its winter quarters in humid west African forests rather than its UK breeding grounds, but nobody really knows for certain. A few days later I heard the distinctive song in another part of the wood, but I’m afraid that both birds were simply passing through, perhaps headed for Wales, and have not been encountered subsequently. A little larger than the chiffchaff and willow warbler, it is also rather brighter than its dingy cousins, having pure white under parts, greenish upper parts and a yellow throat., the whole body shivering as it trills. Unusually among British birds, the wood warbler has two separate, extremely distinctive songs. The commoner accelerating trill is what I heard, but there is a second melody, less frequently uttered, which consists of a series of plaintive, descending “peeooo” notes, fittingly mournful for a bird that is fast vanishing from this country.
Once again a cheeky pair of blue tits have nested in the car park moneybox. The slot for money is only about 18mm wide, whereas the recommended hole diameter for a blue tit nestbox is 25mm! Do we have particularly skinny blue tits at Blean? Probably not, as the slot is considerably longer than 25mm, and the birds are evidently able to flatten their bodies to squeeze through. Equally amazing was the speed at which the nest was constructed. One weekend when I emptied out the coins there were just one or two scraps of moss, enough to make me wonder if the birds were up to their old tricks; the following week I disturbed a bird sitting in what looked like a completed nest. She may already have started laying her clutch, but it is possible she was just fashioning the shape of the cup.
Further information on the wood warbler, including a short video and a recording of its song, can be found on the RSPB website at:
http://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdguide/name/w/woodwarbler/index.aspx
Evening Walk in Church Wood Sat 6th June at 8.30pm.
The walk costs £5 adult non-member, £3 adult member (bring your national membership card to qualify for your concession) Children under 16 free. Booking essential by emailing blean.woods@rspb.org.uk or phoning 01227 464898.