At 2pm on 5th August, an osprey fledging landed on the nest - not one of our birds.

Just to be clear - this is a fledgling - not a juvenile or adult. This means that this bird has only very recently fledged from another nest - a matter of days or a few weeks ago at best.

At the time, our own Pedran, Padarn and Paith were 72, 71 and 69 days old respectively. Our visitor yesterday was probably around the same age.

Here is the fledgling having just landed on the nest perch. She could be a female based on the girth of her legs, but I'm only guessing here, based off a 2-D image.

Of course, the significant thing here is that she is unringed. We've had ringed fledglings land on other Welsh nests before, but I'm not sure we've ever had an unringed bird, especially this early in August.

So, what's going on here - what are the various possibilities?

Here's the video first:

1st Possibility - 5% Chance

She's a fledgling from a Scottish nest (only around half of their nests are ringed each year) and is on her way south on migration.

Well, it's just too early for that to happen really. Youngsters don't tend to start their migration until around 90 days old. That means that both adults would have been back by mid-March and have laid eggs by the end of March.

Below is a chart showing the timespan each of our previous chicks had been airborne before starting their migration; for early-to-normal window breeding years, it's at least five weeks on the wing. This means our fledgling yesterday would have actually fledged her Scottish nest in late June!

Not completely impossible, but highly unlikely. I would put a 5% chance at best of our visitor yesterday being an early Scottish migrating fledgling.

2nd Possibility - 95% Chance

All (known) osprey chicks in Wales are ringed - as far as I know. Same for England.

We know that young fledglings, once they're out of the nest a couple of weeks, start to become more confident and will leave the near-vicinity of their natal nest. But not by much, though.

Our first four chicks in 2011 and 2012 were satellite tracked. None of them dispersed more than around 10 miles from their nest. On the whole, the same is true of other UK ospreys that we have data for.

So by a process of elimination then, this just leaves one realistic possibility: there is a successful osprey nest within the Dyfi catchment, that we don't know about, that has had at least one chick this year.

I think the fact that our old friend, Blue KS7 (Clywedog 2018 male), also showed up at the same time yesterday, was more coincidental rather than anything else. As my old A-level Chemistry teacher used to say, "like attracts like". He was talking about molecules, but the same applies to ospreys - they are attracted to each other. Ospreys are the Hilda Ogden busybodies of the raptor world.

Just now, Saturday afternoon as I am writing this on 6th August, Janine has counted eight ospreys in one camera shot. Well, we can only have five at the most - who are the other three? Is our fledgling back again today? Her siblings? Her parents? All of the above?

No hats, but I would put a 95% probability that our visitor yesterday is a recently fledged osprey from an unknown (to us) nest within 10 miles of us.

And Finally...

So, if this is correct, this is clearly amazingly good news for the conservation of ospreys in Wales. We, Montgomeryshire Wildlife Trust, as well as other organisations in Wales, have nest platforms up in suitable habitats for ospreys, but we shouldn't forget that ospreys can also build their own.

They've managed quite alright for the last 17 million years without us. In fact, most osprey nests in Scotland are osprey-built, as are 99% of the global population's.

From a rather depressing 2021 - just six chicks from four nests in Wales - this year we could have at least eight nests and 20 chicks. We may soon be approaching that ecological tipping-point where an osprey colony is becoming a viable, resilient, self-sustaining population. The next step on a UK level is for these populations to join up: Scotland-Northumberland-Yorkshire-Rutland-Dorset-Wales-Cumbria-Scotland. And everywhere in-between.

This really is extraordinarily brilliant news.

Keep Calm and Look Up