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Friday 6 January 2023

Poop in Post

First, a little jig of joy from me this afternoon. My second go at the Bridport North patch and, more specifically, for Dipper. I tried a different river this time, and had almost reached the northern limit of my patch when...

Yessss!!

A pretty ropey photo, but so far the local Dippers have exclusively chosen distant, dark holes from which to reveal themselves to me. Still, do I care? No.

And now, to the main subject of this post...

Professor Martin Collinson is such a helpful chap. I sent a quick note his way yesterday, received a prompt and positive response, and a blob of bird excrement is now en route to Aberdeen. He did mention that poop can be a bit hit and miss, but I'm pleased he is happy to try. I understand that there needs to be genetic material in the sample, so let's hope the Coly Common wagtail parted with a tiny bit of its alimentary canal, or whatever. Nice. Of course, if I did make an error yesterday, there will be nothing more exciting in it than Pied Wag DNA anyway.

So, on to its other end. Vocalisations...

As I mentioned in the last post, the bird's call didn't sound particularly raspy to my ear. However, having spent some time listening through headphones, to both the Coly Common bird and some Eastern Yellow Wagtails recorded in Mongolia, as well as some Western Yellow Wagtail recordings I made locally over the last two or three years (ie. M. f. flavissima), I am in a better position to say stuff. And what I can say is this: all the calls I have so far heard from the Coly Common bird sound, at best, a little more raspy than flavissima, but fall a bit short of some of the unequivocal Eastern Yellow Wags recorded in Mongolia. Not that this necessarily means a lot. For two reasons:

  1. I suspect there is massive variation between individuals, and even between calls made by the same bird in different circumstances, etc.
  2. What do I know?! I am certainly no expert.

Have a listen yourself. In the following spectrovid are a bunch of calls from the Coly Common wagtail (the first two recorded by Kev Hale on his phone), then a gap, followed by a couple of flavissima recordings from my sound library, another gap, and finally another flurry of Coly Common calls. Interestingly, through headphones the penultimate flavissima call has a noticeably raspy tone. Anyway, see what you reckon...


I thought it might be instructive to compare some sonograms too. In the next pic we have some super-raspy EYW calls from Mongolia, a few from the Coly Common bird, a different (less raspy) Mongolian EYW, and the raspiest flavissima call from the spectrovid above...


The 'raspiness' appears to be imparted on the downstroke. The thicker and more fuzzy/blurry it is, the raspier the call sounds. Having said that, the so-called 'raspy' flavissima note (number 8) is actually thinner and 'cleaner' than all the other notes except number 4.

It's reassuring to see how closely number 3 matches Eastern Yellow Wagtail note number 7.

Lastly, what an interesting exercise that was. I do like a bird that provides a challenge.

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