Friday, 15 April 2022

I Very Nearly Missed It...

I very nearly missed it. Scooting through last night's nocmig, a handful of tiny, sharp marks just about caught my eye. This is exactly as they appeared on the sonogram...

Just enough to look interesting

Playing it back I had a strong suspicion what the bird was. Enlarging and enhancing the blips convinced me - they looked very, very familiar, if not quite so strong as my one and only previous example. Still, for confirmation I posted the recording on the nocmig WhatsApp group.

And yes, it was my second Avocet!

I know...they still look pretty feeble, don't they?

Nocmig really is an education. Not only am I getting better at [some] bird calls, I am also learning a whole new load of stuff about bird vocalisations generally. For example, I am now quite convinced that some nocturnally migrating warblers sing as the go. I cannot remember all the details, but there was some WhatsApp group discussion on this topic a year or two back, with nocmiggers recording the likes of Lesser Whitethroat singing in the middle of the night, in urban, treeless habitat. Surely singing as they flew, rather than while paused briefly on some handy perch?

No Lesser Whitethroats for me personally, but I have recorded several nocturnal Blackcaps, just a single song-phrase each time. I was sure they were in flight at the time, but found it hard to prove to my satisfaction, especially as there is some suitable Blackcap habitat not far away.

However, I have often noticed that local birds which are definitely singing from a low-level perch sound quite different to birds recorded flying over. In what way? Local birds sound like they are singing in a bathroom, with lots of 'reverb' type echo (presumably due to the sound bouncing off buildings etc, en route to the mic) whereas overhead birds always give crisp, clean notes. Which brings me to last night...

I recorded a Blackcap at 03:57, but not just a single song-phrase this time. Rather, four rather stilted phrases over about 40 seconds, the first and last being quieter, suggesting the bird was flying over. A local Robin was singing at the same time, at a roughly similar volume. Here they both are, with all the gaps cut down. Note how the Robin has that 'singing in a bathroom' kind of tone, versus the 'clean' notes of the Blackcap...


And here is what some of those notes look like on a sonogram...


 

So there we go. If that Blackcap was over in the trees somewhere, I have absolutely no doubt that there would be similar 'shadows' and fuzziness - I get it from all the local birds that sing at (or before) first light. This is enough to convince me that those occasional nocturnal bursts of Blackcap song are given by migrating birds as they fly over. Why only Blackcaps? Yes, another interesting question...

I shall close with a bit of Oystercatcher action from last night. Probably my favourite nocmig recording of Oystercatcher yet. It is well worth a listen. I wonder if I will ever cease to be amazed at the birds which fly over at night? I hope not.

2 comments:

  1. Excellent Robin vs Blackcap comparisons. And blimey, I thought that Oyk was gonna explode out of my laptop screen it was so damn close!!!

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    1. Thanks Seth. I've had really close Oycs once or twice before, but never a continuous series of calls like that. Would love to have been outside to hear it. 😁

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