Of interest to the Ornithologist among us.

[grumpydad]

It has just occurred to me that a few weeks ago while I was riding over the mountain road towards home, I was followed for a short while by a bird with a rather strange yet very distinctive call, anyway I was wracking my brains trying to match the call to the image I had in my head, I couldn't see the bird as it was getting on for 7pm and pitch black, anyway the only one that kept coming to mind was a Nightjar, which is ok except, they don't usually get to the UK until April, so March 11th is a bit out. I don't think you can mistake the call for anything else, unless you know different https://xeno-canto.org/359355 and when you're on the mountain in the dark that noise certainly makes you pick up the pace a bit sharpish

 

[Gwylan]

Look for the app Merlin.
Samples the bird call and suggests what it is.

 

[HLaB]

https://road.cc/content/news/jeremy-vine-prank-wins-april-fools-day-307587

 

[geocycle]

Merlin is great and free. I have used it for a couple of years and am slowly getting better with recognising calls. It doesn’t use much battery or data.

 

[Poacher]

Campag freewheel?

Certainly a distinctive call, and it's not outside the bounds of possibility that you heard an early arrival.
Are Nightjars regular in that area?

 

[Jameshow]

https://road.cc/content/news/jeremy-vine-prank-wins-april-fools-day-307587

I think the bird of prey was after some chips.... !

 

[Dave 123]

Are you sure you didn’t have a few jars beforehand on that night?

As you say it’s usually much later on that they arrive and start calling, but that’s not to say it was an early bird…. I’m just off to google

The best it came up with was APRIL.

Who knows, you could be right.

 

[grumpydad]

Campag freewheel?

Certainly a distinctive call, and it's not outside the bounds of possibility that you heard an early arrival.
Are Nightjars regular in that area?

I have heard them in the past, but that was over the summer months