Monday, 22 June 2009


Skulking singing male MARSH WARBLER at Amwell NR on 21 June 2009 (Phil Bishop)
With the relocation of the Royal Tern in North Wales on Saturday afternoon, I was unfortunately otherwise engaged when Mike Ilett and others confirmed the presence of a singing MARSH WARBLER at Amwell that evening and it was not until this morning that I finally had the opportunity to see it (it had stopped singing when I arrived at 2100 hours last night).

As it was, I spent from 0930-1200 hours at the site this morning, during which time the bird was singing almost continuously and was showing well intermittently. I enjoyed several prolonged full-frame 'scope views as it sang from the large Willow bush. It is a very intriguing bird.

It has a rather slow-paced song, is rather quiet and subdued and does not have the typical repertoire of a singing Marsh Warbler (certainly not during the period I listened to it). The only recognisable mimicry was of Blue Tit and Barn Swallow but most concerning was its ability to repeat numerous phrases and loud sounds most typical of Blyth's Reed Warbler (although others have heard it mimicking Common Blackbird and other common species).

I was also most taken aback by its appearance. In cold light, it did appear very pale brown on the upperparts with a slightly paler rump but completely lacked any olive tones. It did not have any obvious whitish tips to the primaries but did have paler tips, identical in colour to the fraying at the edges of the flight feathers. Its legs were distinctly pink or pinkish-grey and the undersoles of the feet (clearly seen in the 'scope) did not appear to be bright yellow and the claws were dark. There was certainly no direct contrast. The bird also had a noticeable whitish eye-ring, a supercilium that extended behind the eye, the head was not particularly rounded and the bill was quite pointed and long (not blunt-tipped).

Certainly the primary projection (with 7 visible primary tips) indicated Marsh Warbler and eliminated Blyth's Reed Warbler but the inconsistency in other features perhaps indicated it was a first-summer bird. This may explain the song delivery and limited variability.

Throughout the observation period, the bird was singing from the Willow bush or from the thick vegetation adjacent, and often spent periods foraging on the ground. At no point, did the song revert to a Western Reed Warbler type, which has happened with 'Mead Warblers' in the past.

DETAILED DIRECTIONS: Take the A414 east from the A10 and at the first roundabout, take the B181 towards Stanstead Abbots. Crossing the small roundabout in the town, turn left before the railway on Amwell Lane and continue NW for just under a mile and park carefully on the right-hand side of the road at TQ 375 126. Follow the track NE to the railway crossing and 50 yards further on, drop down on to the canal towpath (west side of the canal) and walk NW towards Hardmead Lock. Continue for a further 350 yards until you reach a small bench about 150 yards before the main lock. Just before the bench is a gap in the hedgerow from where the obvious Willow bush can be viewed (at cTQ 373 132).


The Marsh Warbler is a very rare vagrant to Hertfordshire, with very few confirmed records - just six in fact. The first few records related to a crop of sightings around Wilstone Reservoir, Tring, in summer 1941 and 1942, followed by a host of claims including breeding at Rye Meads in 1960 and 1961. These records all appear to relate to misidentified Western Reed Warblers.

1) The first acceptable record relates to a singing male at Stockers Lake from 25 May until 4 June 1978 (John Magee et al; published record in British Birds 73: 23). This followed an almost certain singing male at the same site on 28 June 1976 (per Richard Drew).

2) One was trapped and ringed at Water End, Wheathampstead, on 8 June 1980 (Tom Kittle).

3) A male was singing from a Raspberry thicket at Northchurch early on 5 June 1988. It was trapped and ringed and remained present the following day (Johnne Taylor, John Marchant, et al)

4) A singing male present at Rye Meads from 22 May to 19 June 1993 had been ringed as a juvenile (Ring Number: H154925) at New Hythe GP on 23 July 1991 (Alan Harris et al, fully documented in 1993 Hertfordshire Bird Report on pages 178-179).

5) A singing male was present at King's Mead, Hertford, on 28-29 May 1994 (Graham White, Mike Ilett).

6) A singing male was present at Broxbourne GP from 30 May until 3 June (Steve Connors David Booth, et al). The bird was trapped and found to be previously ringed as an adult (Ring Number 3858928) on 26 July 1991 at Veurne, West Vlaanderen, in BELGIUM (Adam Wilson).

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