Thursday, 2 September 2021

Buses and Cricket

First, a few pics from a brief visit to Cogden after work today. A group of 3 Spotted Flycatchers provided a photo opportunity of the kind I rarely get. Normally I'm too busy birding to want to spend much time sneaking and creeping, but this afternoon a whacking great gatepost was almost big enough to hide me completely...

Two of the three Spotted Flycatchers...and a Robin

I think the blurry yellow fly highlighted against its belly is the object of this bird's gimlet gaze.

Spotted Flycatcher - a rare portrait.

Apart from two Whinchats I saw little else in a quick tour of a handful of fields, but down on the beach...

1cy Yellow-legged Gull

This bird was very uncooperative and belted off a bit too rapidly, leaving me with some woeful flight shots, but then I spotted another just along the beach with a few Herring Gulls, an absolute peach. No juv YLGs all summer, then three in three days, like the proverbial buses...

Excuse the photographic excess, but it really is rather lovely...

Yellow-legged Gull. Definitely a rose among thorns.


A right poser. It's almost as if the bird knows how brightly it shines amongst its dull cousins.


Okay. Last one.

So. After dinner this evening I spent an hour or so loitering by the magic Whinchat field at West Bex. The best Whinchat tally I could muster was eight, but that's not why I was there...

Two days ago I was in exactly the same place a little after 16:30, making a poor job of getting Whinchat record shots, and became aware that I could hear a cricket 'singing' just behind me. There was something slightly odd about the sound, and I turned around to investigate its source. A few yards away on the main coast path a couple were walking by, and as I struggled to locate where this sound was coming from I suddenly realised it must be a mobile's ring tone, and expected one of them to whip out a phone. But no, they carried on oblivious. Meanwhile, the crickety noise continued, and yes, it was definitely somewhere close by. And then I twigged what was so odd about it, and why I'd thought it might be a ring tone. Basically it was the most clichéd cricket noise you can imagine, like you would expect to hear in the background of a movie scene. Annoyingly, at this point it stopped, so I turned back to the Whinchats.

A few minutes later it started up again and this time I was ready. I fired up the camera's video function and tried to get as close as possible. I recorded about 30 seconds, but probably got too close because it stopped again. Ah well, better than nothing. I carried on birding and thought little more about the cricket...

Yesterday evening I thought I'd better investigate my cricket and extracted an mp3 file from the video. Next step: consider the most likely candidates. How about Great Green Bush-cricket? Nope, it seems bush-crickets all have very high-frequency songs, which this wasn't. So I downloaded a sound file that claimed to include 'all' the UK Orthoptera, and went through the lot. Nope. Maybe it's not a cricket at all? As a last resort I posted it on Twitter and asked for help. Fellow blogger Steve Gale was straight on the case. 'Sounds like Tree Cricket', he said...

I'll cut a long story short, but suffice to say that Italian Tree Cricket Oecanthus pellucens is a European species and recent UK colonist. A whole bunch of them were discovered at Dungeness, Kent in 2015, where there is a now a thriving population. Steve is a Dungeness regular, hence the familiarity.

It seems the insect's arrival at Dunge was the result of a natural range expansion, following a jump to the Channel Islands a few years earlier. Apparently there has been a very small number of occurences elsewhere in the UK...though possibly not Dorset so far. But let's not jump the gun...

First, was my cricket actually a Tree Cricket?

On Xeno Canto there are several recordings of Tree Cricket, and after playing a few it was obvious why Steve had suggested it. Here is a spectrovid comprising a few seconds of the West Bexington cricket followed by a few seconds of a Tree Cricket recorded in Germany...


And here is a bit of spectrogram analysis...

West Bex cricket sp vs Tree Cricket from Germany

Despite my recording being very quiet and blighted by wind noise, it is still possible to discern three distinct bands, beginning with the strongest at just over 2.5kHz. On Xeno Canto the lowest band ranged from around 2.5 to 3kHz, and was always the strongest. The number of notes in each phrase, and the speed of repetitions, is variable from cricket to cricket. The shape of each note is clearly the same as well, again despite the feebleness of my spectrogram.

As far as I can tell, there is no confusion species that might queer the pitch. So. The only conclusion I can draw is this: on 31st August 2021, at 16:45 I heard and recorded a Tree Cricket Oecanthus pellucens at West Bexington, Dorset. Unfortunately I didn't hear and record one on 2nd September.

As one local birder put it, cricket identification is a bit niche. I cannot disagree. However, it must be said that I am not the world's best rarity-finder, and if the only way I can find a first for Dorset is by analysing the stridulation patterns of a random cricket which throws itself at me, I'll take it!

4 comments:

  1. Congratulations, any 'first' is an accomplishment and insect followers (I'm sure there's a word for them), will envy you. Great Spotted Fly pic too.

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    1. Thanks Dave. 👍
      This cricket episode is definitely one of the most bizarre natural history encounters I've had. Very strange...

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  2. "how brightly it shines amongst its dull cousins" - marvellous! I can't see past its dull cousins to be honest - they all look the same to me! did i say that out loud?

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    1. Ha ha! I sometimes forget that gulls are not necessarily everyone's cup of tea!

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