Today, Clarach is 74 days old and Cerist 72 days. So the big question... When will they start their migration?

Here's the easy answer - British ospreys tend to start their migration between 80 and 110 days old, the average being somewhere in the middle.

So that's not very helpful really. Let's look at the ages when the four Dyfi fledgelings have migrated in 2011 and 2012:

Einion = 87 days
Leri = 98 days
Dulas = 98 days
Ceulan = 97 days

Ceulan prepares for Africa in 2012

The average of the four birds is 95 days, so if Clarach and Cerist left at this age, they're going to be around for another three weeks - the last few days of September or early October. However, we know that both girls were a healthy 1.7Kg when they were ringed, plus, time is getting on. Will these two factors have an effect?

Cerist - Don't ask me, I don't know!

If I had to guess, I'd say 'probably', and hazard a guess at somewhere between September 20th and 25th. But, and this is a big BUT, there is absolutely no way of estimating with any degree of certainty. This is not like guessing incubation times of eggs, for example, where you can judge to within a day or two the hatching of chicks. Many a hat has been devoured playing this game.

Much will decide on Monty. Will he go before his daughters? Maybe, maybe not.

He migrated on September 5th last year and September 11th in 2011. Problem is this year, he has some of the latest chicks on record on his hands that ordinarily wouldn't go for at least another three or four weeks. Glesni left him with sole custody of the kids on 31st August.

Monty will have two conflicting neurological triggers to juggle right now. The urge to fly south because now is the right time, and the paternal urge to stay and feed his daughters, thereby maximising his genetic investment this year.

There will come a time, probably in September, when the first urge becomes slightly stronger and the scales are tipped in favour of migration and he'll be off. Thing is, no one knows when this time will come yet - not even Monty.

Another crow intrusion, how many more of these will he have to endure on the Dyfi this year?

THE BIG FISH COMPETITION

We're keeping the Dyfi Osprey Project open for an additional month including the Live Streaming, we'll close now September 29th. To help pay for this, here's the last competition of the year!

Up to Sunday evening, September 8th, the total fish catch for the season was 478. The competition is easy..

What will be the total fish catch in 2013?

A professionally framed A3 photograph of Glesni in flight with seaweed to the winner - we'll send worldwide. (Update: or the Clarach with wings back, see image below - you choose) So for example, if you think the total for this year will be 530, just put that number below in the comments section, or on the Facebook post.

Usual rules - Donate a minimum of £2 per entry/guess (via MyDonate button on the website), as many go's as you like. The last date to enter will be midnight next Sunday evening - Sept 15th. If it's a draw, we'll pull lots.

So, to give you as much information as possible to make an 'educated' (lol) guess, you need to first figure out an ETD - Estimated Time of Departure, and secondly, how many fish caught between last Sunday and then. Simples.

Here's the total fish count so far to guide you - 478 all together up to Sunday night.

Remember, it's total catch that we record, so even if either Clarach or Cerist start fishing for themselves, we'll count these. It's the total fish count for the year, irrespective of who caught the fish. We even count the dropped ones!

Someone's floundered

That's it. Good luck and thank you for helping us at Montgomeryshire Wildlife Trust stay open a little bit longer to see off these beautiful birds.

A3 print of this gorgeous photograph of Clarach (or Glesni), professionally framed, to the winner.