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A Hat-trick for Telyn

Posted: Friday 22nd April 2022 by Emyr MWT

Telyn has laid, for the fifth year running, three eggs.

Telyn completes the Hat-trick!

3rd egg arrived at 17:07 on 22nd April. Will this be the full clutch? We'll have to wait and see.


23rd April

Telyn incubated her three eggs all night except for a quick toilet break just before 5am.

Osprey chicks take between five and six weeks to hatch, so eggspect the first sign of life from around 23rd May onwards.

We can see the ospreys at night thanks to an infrared lamp on the camera pole. This is light at the long end of the spectrum that is not visible by humans nor any other mammal. Birds can't 'see' infrared light either; no warm-blooded animal can.

Fear not, we don't have a nocturnal ink thief - those three eggs in the nest have pigmentation on them, it's just that the IR light can't see it. 

Ospreys bring all sorts of odd material in to their nests - what do you reckon this is, a sheep's jaw?

25th April

Most female ospreys lay three eggs, sometimes two if there's been some kind of drama.

However, around 5% of clutches in the UK will have four eggs. Maya at Rutland, for eggsamaple - Telyn's mother - has had several 4-egg clutches.

So what determines the amount of eggs a female osprey will lay? Well, several factors really.

Predation pressures play a part, the strength of the bond between a pair, how early both birds are back from migration, the fitness of both birds and, perhaps most importantly, the amount (and quality) of food available.

This latter food factor (sometimes called Ashmole's Hypothesis) may well give us a clue as to why we've never had a 4-egg osprey clutch in Wales to date. The amount of fish is rarely a problem, but the calorie density may be lower than at some other sites where oily fish are exclusively the prey item.

Yes, oily fish are a major part of some Welsh osprey pairs, but we've yet to have a 4-egg clutch in Wales that we know of.

If Telyn was going to lay a fourth, it will be later on this afternoon, three days after her third egg.

Unlikely, but you never know. Keep Calm and Look Down.  

26th April

No more eggs overnight, so we can (almost) safely say now that Telyn has a 3-egg clutch again this year.

Over the last five years she has laid 15 eggs in all: 3,3,3,3 and 3 (2018 - 2022). She now becomes the record holder for this nest, overtaking Glesni who laid 13 eggs, also during a five year period (2013 - 2017).

Blog and video later this week...

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