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Saturday 26 August 2023

The Ictodious Warbler

A curious consequence of our digital age is how much it is possible to enjoy a bird that you don't even see. And so it was yesterday, when Kev Hale discovered an Ictodious Warbler on Beer Head, near Seaton.

Why so much fun for me? For a start, Beer Head is responsible for many fond birding memories, and I'm always pleased when it turns up a goodie. Also, it is long overdue a confirmed Icterine or Melodious Warbler, so I was chuffed that Kev got a photo which appeared to nail the ID. But there were a couple more aspects which added another level of delight. Number one, the bird's identity suddenly got all controversial, and I had a great time wading into the debate from afar. Number two I will get to shortly. In the meantime, back to that photo...

The thrill of finding a good local bird is all too rare, and the last thing you want to do on such occasions is botch the identification. So when a yellow-tinged Hippolais warbler pops out in front of you, the pressure is on to clinch it as either Melodious or Icterine. Down here in the Southwest, Melodious is by far the more likely species, but Icterine is always a possibility. So what do you do? A lot of birders these days are faced with a dilemma...

  1. You observe it carefully, checking for and ticking off salient field marks.
  2. Or, you frantically dig out the camera and pap away like crazy, hoping to convert said field marks into pixels that you can later analyse at leisure.

Realistically, at somewhere like Beer Head, where birds are often through and gone in the blink of an eye, option two makes a lot of sense. Especially for a warbler. That's certainly the way I would have played it. And it's what Kev did.

Also, with their built-in image stabilisers, modern cameras can minimise the effects of that involuntary adrenaline surge. Binoculars, not so much.

Anyway, having got less-than-clinching views, but a couple of shots, Kev put a message plus pics on the local WhatsApp group. Pretty quickly there was broad agreement on the bird's ID, and the news was passed on to BirdGuides, one of the bird information services. Here is the best photo...

The original was a bit over-exposed, so this is a tweaked version. (Photo by Kev Hale)

Possibly you are now thinking, 'Well, I see a vividly pale wing-panel, obviously pale-fringed greater coverts and what looks like a massive primary projection. It has to be an Icterine Warbler.'

In which case you are in great company. That was yesterday morning's consensus, and what BirdGuides published on their news service. But shortly after that, the BirdGuides bods took a closer look at the photos Kev had sent them. They came to the conclusion that the images actually depicted a Melodious Warbler, not an Icterine, and updated their news item accordingly:

Melodious Warbler...Beer, Devon...1st-winter in hedge, blah, blah...(not Icterine Warbler; reidentified from photographs)

Okay, they didn't actually highlight that crushing phrase 'reidentified from photographs', but they might as well have. The gauntlet was down...

I set to work with Kev's photo, producing what I thought would be incontrovertible evidence for the Icterine defense...

Even without the supporting features outlined earlier (and others which weren't) that many visible primaries rules out Melodious.

And, though crudely measured, the primary projection is way too long for Melodious.

By way of comparison, here is a Melodious Warbler I photographed in 2010 on St Martins, Scilly...

Interestingly, this bird had initially been identified by some very capable birders as Icterine.

However, The BirdGuides team were not persuaded so easily. There is more to this saga, but better that you read it here, on Steve's Waite's excellent blog.

But all's well that ends well, and I am pleased to say that the controversy is no more. This morning, on BirdGuides...

I'm not quite sure about the 'reidentified from photographs' bit, but fair play to the BirdGuides team for putting out this correction today. They are an excellent and very helpful bunch, just fallible like the rest of us.

And the final reason I was so pleased about this bird...

Many years ago (2006-ish?) a less-experienced Kev Hale found a probable Melodious Warbler on Beer Head. Good views, but no camera in those days, and the ID was never nailed to Kev's satisfaction. How appropriate that he should find the Icterine.

Meanwhile the Axe patch still awaits its first Melodious Warbler.


And so to moths...


Thursday night, 24th August

97 moths of 37 species. None new for year, but a couple worth photographing...

Despite 2023 seemingly not being as good for migrants as last year, this is our seventh Rusty-dot Pearl. By this time in 2022 we had caught just five.

Magpie Moth. Only our third this year.


Friday night, 25th August

Just 62 moths of 30 species; one new for year and garden.

Recent weather has not felt conducive to a good haul of moths, and there has been a sameness to catches lately, with Yellow Underwing, Uncertain/Rustic agg. and A. tristella in numbers, but not a lot new. So it was good to step outside into the morning gloom and spy an interesting moth on the cabin window. Momentarily I wondered if it was our second Jersey Mocha, but corrected myself straight away. Nope, that wing shape looks a tad off...

Sure enough, the garden's first, much hoped-for Clay Triple-lines.

I was intrigued by how sure I felt that this moth was not Jersey Mocha. That species appears to be exactly the same shape as Blair's Mocha, and I see a lot of those. So I wondered exactly how much difference there is, shape-wise, between Jersey Mocha and Clay Triple-lines...

Not much! That forewing is slimmer and more pointy, but the difference is subtle. It's pretty amazing how the eye can nevertheless discern such nuances with a bit of practice.

Probably because we've done well for them, I particularly like the Mocha family. But I think that's probably it for the Cyclophora I'm likely to trap here. Chances of the other three are slim to zero. Birch Mocha: just one Bridport area record on the Living Record map. Dingy Mocha: though apparently regular in East Dorset, no West Dorset dots at all. False Mocha: dream on; no recent Dorset records, and very few anyway. Still, you never know...

There were one or two other bits worth a pic...

This battered Black Arches is our first in almost three weeks. We did have a good run of them through July into early August, but I guess they must all have been males, because I could not believe the size of this beast! Females are a good 10mm longer than males, and that translates to a vastly increased acreage!

Female Black Arches even gives Old Lady a run for its money!

We've trapped a few Dark/Grey Daggers this summer, and had another last night...

Dark Dagger...or Grey Dagger.

I understand that it is possible to ID males to species without resorting to dissection. Apparently the process involves a gentle, if undignified, squeeze, and a quick inspection of what is revealed. This is a bit beyond my abilities, but I have nevertheless been able to add Grey Dagger to the garden list by other means...

It may be young, but it is still a Grey Dagger. The caterpillars are distinctive. This one is anxious to get back to its feast of Cherry Plum leaves.

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