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Blue 24 Lays an Egg

Posted: Sunday 17th April 2016 by Emyr MWT

Blue 24 Lays an Egg

Blue 24 has laid an egg.

At 12:10 this afternoon, Blue 24 got up from a sitting position at the other platform on Cors Dyfi (we call 'new nest') and looked straight back onto what must be an egg. She stared at it for a while before sitting down again and has been incubating all afternoon.

Around an hour earlier, I managed to get this short video using the video thingy on my SLR from the 360 Observatory:


To reduce confusion, let's refer to the main nest as NEST 1 and the new nest as NEST 2

Dyfi nest = NEST 1; New nest = NEST 2

Ever since Monty arrived back at the Dyfi on 3rd April, he has shown Blue 24 a lot more interest than in previous years. We've seen subtle changes in Blue 24's behaviour this year - she now tolerates people on the boardwalk and 360 Observatory for example, while perching on Nest 2. She usually flew off last year at 09:45 when we opened the Observatory in the morning.


This kind of breeding strategy is called polygamy. A polygamous situation occurs when one male breeds with two females concurrently and this happens a lot in birds - even birds of prey like ospreys.

We have a unique situation at the Dyfi. Since we opened the 360 Observatory in 2014 we have unparalleled views of the Dyfi nest and the whole Dyfi environment - we can see the ospreys literally miles away and observe them practically for 100% of their five months with us every year. Five High Definition cameras and 24 hour continual recording help as well!

Monty and Blue 24 on Nest 2

This means that we get to see things that a typical nest watcher with a telescope will never see. An insight into the breeding life of an osprey that is almost unprecedented. I will write a blog about polygamy in ospreys later this week, but for now, please bear one thing in mind:

Polygamy is a lot more common than we think in ospreys. Dai Dot has been mating with Blue 24 since his partner returned this year and Aran has been observed at the Glaslyn mating with Blue 5F around two miles away from the main Glaslyn nest over the weekend. Please bear this in mind when viewing comments especially on social media.

It is not Monty's fault, it is not Blue 24's fault. It's nobody's fault. These are ospreys and they are behaving like ospreys. We should not judge them by human standards (whatever those are these days).

Right, having said that, here's a timeline of key events this afternoon:

11:35 - 12:10 Blue 24 low in Nest 2.

12:10 Blue 24 gets up, looks down and shuffles. Behaviour typical of having just laid an egg, then settles to incubate.

14:25 Monty brings whole fish (sea bass) to Glesni on Nest 1.

15:15 Glesni eats some of the bass on the low perch and returns to the nest with the half-eaten fish.

15:38 Monty takes the fish to his feeding perch to eat himself, then takes it to Blue 24 on Nest 2. She feeds on the perch close by and Monty takes over incubation.

16:21 Blue 24 comes back to Nest 2 with fish. Monty chases away a crow.

16:24 Monty back on Nest 2, mating with Blue 24.

17:20 Changeover and mating with Blue 24.

17:25 Monty flies off, downriver.

18:57 Monty brings remains of bass to Glesni.

19:02 Monty and Glesni mating.


Monty brings Glesni a sea bass - before sharing it with Blue 24


This polygamous situation has naturally opened up a brand new can of worms in osprey-land and generated a whole new set of questions. We don't know the answer to all of them, but here are a few of the most often asked questions we've seen people ask this afternoon:


1. Who is the Father?

Monty - no question. Dai Dot mated with her for around 30 minutes on 3rd April for the last time that we know of. Monty has been bonding with her daily since he returned on the same day. So this is DAY 14 for Blue 24.


2. Will Glesni lay eggs?

Almost certainly yes.

3. Is there a camera on the new nest?

No - we were going to put one up this week! We're too late now and don't want to disturb the birds.

4. Can a male osprey raise two families in two nests in the same season?

There is usually a compromise somewhere and productivity at one (or sometimes both) nest will be reduced or fail. For Monty to raise chicks at both nests he will need, more than anything, luck. Good weather, minimal predation pressures and no disturbance. Only time will tell.


5. Will we provide 24 hour nest surveillance to both Nest 1 and Nest 2?



6. How close to the main nest is the other platform?

Around 300m.


7. How close to each other can osprey nests be?

Depends totally on the birds themselves. In Florida, just a few metres away - 50m maybe. In remote parts of Scotland, over a mile away. There is no correct answer.

8. Why did you build it there and within eye sight of the main nest?

We were instructed to do so by the regulatory authority in 2010/11 and take the main nest down. Because Monty bred on the main nest in 2011, we couldn't take it down as it was now a breeding Schedule 1 bird of prey nest; we would have been breaking the law.

9. Will we rename Blue 24?

No, we'll still call her Blue 24.


10. Will we intervene in any way?

Absolutely not - this is nature and we have no reason to intervene.

So much for the quiet year we were hoping for! Polygamy blog coming in the next couple of days..






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