Dusky Warbler in Nottinghamshire

Phylloscopus fuscatus: Netherfield Lagoons, October 7th 2007

On Sunday 7th October at 14:58 I received a phone call from Peter Smith to say that he, Neil Matthews, Neil’s brother Paul and Darren Matthews (no relation) and had seen and heard briefly a Warbler at Netherfield Lagoons earlier in the day and that he had concluded that it might be a Dusky Warbler. I was immediately somewhat sceptical but went over a few identification points with him and it sounded at least possible. I asked him if anyone was trying to relocate the bird and he told me that he was going back to the site shortly. I asked him to keep me informed. Shortly after this phonecall I informed Bernie Ellis and Steve Dunn of the report. As I had some shopping to do, I decided to hold back and wait for developments.

At about 16:00, I received a second phone call from Peter to say that he had relocated the bird and that he was still of the opinion that it was a Dusky Warbler. At this point the only information on the bird was that it was a phylloscopus warbler with a noticeable supercillium and a monotonous tacking call, somewhat less harsh than Blackcap. I informed Steve Whitehouse at Birdguides and again BE and SD, to say that it was a probable Dusky Warbler. This provoked more scepticism, but I persuaded them that the bird was worth a shot. These in turn informed Tony Critchley, Paul Naylor and others. The bird had also hit the pagers by this time. I managed to arrange a lift to the site at about 16:30, not quite knowing what to expect.

About a dozen observers were already at the site when I arrived including BE, PN and SD. The bird had been seen in a dense area of scrub adjacent to the river Trent and the viaduct. After about 20 minutes, everyone was amazed to hear what was clearly a Dusky Warbler calling from the scrub. A number of observers present were familiar with the species and the call alone appeared to remove any doubt. Clearly though it was important for someone else to see the bird and obtain a description. In the following hour or so the bird showed twice and views obtained were dependent on one’s position. However it continued to be quite vocal and was last seen flying across the river to Radcliffe in failing light.

The best views obtained were by Nigel Davis, John Szczur and Tony Critchley. Their notes are reproduced below as well as an account of the find by PS.

Peter Smith's account

At about 10:00 I was birding at Netherfield with Darren Matthews, Alan Edge, Neil Matthews and Paul Matthews when, by the river, near the railway bridge a bird gave a call that I did not recognise, it sounded a bit like a Blackcap, but not so harsh, yet quite percussive. It was calling from dense cover as it moved along the river bank.

There were several other birds with it, including Robin, Wren, Dunnock and Blue Tit but eventually Neil saw a bird that looked like a Chiffchaff. It doubled back giving the merest of glimpses until I saw it creep up a sapling like a Tree-creeper. I saw a strong supercilium and fine bill and a suggestion of mottling on the cheeks. It was pale beneath and, as it flicked up and then into cover, I saw a brownish back. The river behind the bird was reflecting light quite strongly so the bird was almost a silhouette and detail was very hard to see, especially with the briefness of the views.

The bird then disappeared and went quiet and after a short while we carried on around the lagoons. Neil suggested it might be a Dusky Warbler and when I got home I consulted my books. The combination of the call and Chiffchaff-like appearance indicated Neil was probably right and spurred me to call Darren and suggest we go back, and I alerted Andy Hall on the way.

Account and description by John Szczur

After waiting over half an hour overlooking a relatively small but dense patch of cover and only having seen a Wren a few times, I was beginning to wonder whether the bird reported as a possible Dusky Warbler was still present. I then heard a call which caught my attention because it sounded like a Dusky Warbler. At the same time, I noticed a bird moving energetically up and out a bramble patch and into more open willow scrub. The bird showed well, often perched sideways on, for about 20 seconds.

First impressions were of a dark bird the size and shape of a Chiffchaff which, whilst calling, was flicking both its wings and holding its tail in a slightly raised position. I was immediately struck by the birds obvious supercilium which was long and prominent both in front of and behind the eye. The ‘super’ extended well behind the eye becoming pointed close to the nape. The fact that the supercilium was bordered below by a strong black eye stripe and above by a blackish margin made it all the more obvious. The upperparts i.e. crown, nape, mantle, wings and uppertail were an evenly coloured dark grey-brown, except for a blackish patch on the alula. The underparts were a fairly uniform buff-brown, but with the bird showing whiter areas on the throat and belly. Unfortunately, the undertail coverts were not seen. Although the birds plumage appeared quite dark in what was fairly dull light, the contrast between the darker upper and paler lower parts was still evident.

As previously stated, the general structure of the bird was very similar to that of a Chiffchaff. The wings were short because of a short primary projection which I noticed when the bird was flicking its wings. The tail was the same shape as a Chiffchaff, moderately long in proportion to the body with a ‘squarish’ end. The bill was fine and pointed with a dark upper mandible and paler lower. The eye was black. The leg colour wasn’t noted.

The call was a short surprisingly loud ‘tak’. It was repeated about twice a second when the bird first appeared and seemed excited. The call could easily be mimicked by ‘clicking’ ones tongue. If I had to choose another species that its call most closely resembled, I would have to plump for Lesser Whitethroat. The call was given occasionally as it moved through cover, although it was quiet for most of the time. It also called a few times on both occasions when it flew.

It is worth noting that at one stage the warbler moved into the crown of a 4m tall hawthorn tree and, although still a devil to see, when it was seen it appeared to be feeding comfortably and did so for several minutes.

Following the original sighting, I had a further three shorter ones; once in the open in moderate light but only for about five seconds; moving around in the crown of a hawthorn but silhouetted; and finally, in flight as it crossed the river Trent. These later views all confirmed my earlier impression that I was watching a Dusky Warbler.

Description by Nigel Davis

A phylloscopus warbler, similar in shape to Chiffchaff. The first view was from a position looking down on the bird slightly and angled from the rear, as if the bird was looking back at me over its shoulder at a distance of five to six metres. The second view was from a position opposite to the first, just below eye level and slightly closer. The bird held an alert stance, flicking both wings and tail. The most striking feature was the prominent supercillium, narrow and whitish in front of the eye becoming broader and buff toned as extending behind the eye, tapering out into the nape. There was a thin, dark eye stripe.

The upper part colour was of a dark brown, contrasting softer pale brown flanks. The breast, belly and vent were whitish.

The shortish folded wings made the brown tail appear long.

The bill was short, fine, sharply pointed and appeared dark, although the lower mandible seemed to show a paler base.

The legs were dark.

Call - a sharp repeated tacking.

Description by Tony Critchley

A medium sized Phylloscopus warbler similar in shape and size to a Common Chiffchaff, dark grey-brown above and paler greyish-white below. It had a long striking pale/off white supercilium that was thinner and well defined in front of the eye, broadening above the eye and a dark eye-stripe. The bill was fine and pointed. I didn’t particularly look at the under tail coverts but wasn’t aware of them being noticeably apricot in colour as Radde’s Warbler (Phylloscopus shwarzi) often are. The bird was skulking and elusive, often remaining and calling in deep cover.

Call - a harsh ‘teck’.

Other issues

Dusky Warbler was one of the species removed from the BBRC list in January 2007. Dealing with such a rare bird, especially in land, clearly raised the question of how the record should be properly ratified. The BBRC made no special recommendations in this regard when this and the other species like Radde’s Warbler, Red-rumped Swallow, Black Kite etc were jettisoned from their list. They accepted that there was enough expertise at the local level to handle such species correctly. The record was submitted by the finders and the fact that four of the Notts Birders Records Committee saw the bird, strengthened the case for in-county scrutiny.

Reference needs to be made to the events of the 16th December; when one of the finders of the bird appeared to have relocated it, more than two months after the original observation. This elicited considerably more interest than on October 7th but the ensuing twitch failed to locate a Dusky Warbler, instead finding that the bird was a Cetti’s Warbler. Several of the observers of the October Dusky Warbler saw and heard the Cetti’s and were confident that the two birds were not the same.

Andy Hall - February 2008