Posted: Tuesday 12th December 2017 by Emyr MWT

Here are the 24 advent photos and stories we are showing on our DOP Facebook page at the moment:

ADVENT: 25th December


This year's Christmas Blog is a bit different.

Only one of the eight breeding ospreys in Wales is ringed, so they cannot be Welsh or English birds right?

For the first time publicly, we present a hypothesis that explains away this awkward ecological contradiction and reveals the origin of most of these birds.
It's a bit longer than usual, there's quite a lot to get through. Do you agree that this explanation is plausible?

Find a quiet few minutes if you can, grab your favourite Christmas tipple and let us know. BLOG HERE


ADVENT: 24th December

After the sadness of last year, what better way to end this season with another three-chick family, the third time we've had a three fledgling brood in seven years (2011 - 2017).

We hope you've enjoyed this year's Advent, it was intended as a bit of a catch-up for those of you guys that are relatively new to DOP and as a reminder to those that have been with us for some time.

Look out for the last in the series tomorrow - it's a special one. You didn't think we'd forgotten him did you!

And of course it's The Christmas Blog tomorrow. No snooker or violins this time, promise.. 

ADVENT: 23rd December

If ever we've had a year of both joy and sadness all mixed into one, it was 2016.

Tegid (left) and Ceri.

ADVENT: 22nd December

We were looking forward so much to the 2016 season. We had just installed our first Ultra High Definition 4K camera, quite possibly a world first. Monty and Glesni had produced their first three-chick brood the previous year and eggspectations were high for another hat trick.

However, before the main event we had our usual warm-up act. Blue 24 arrived back first on 25th March followed a few days later by her old friend Dai Dot.

As they got down to business they were joined by another Rutland female - Blue 5F, who also took a fancy to Dai Dot and the nest. And so ensued a female battle for the nest, a nest that neither of them 'owned'.

Blue 24 was stationed in the centre of the nest, protecting it, and herself, from a 360° aerial bombardment from her Rutland cousin.

When we put this image up of Blue 5F dive-bombing and up-turning Blue 24 on 1st April, it was so remarkable people thought it was a wind-up.

It wasn't, and we had to put the full video up to prove it! It was all down to the new 4K camera that you helped fundraise for :-)  


ADVENT: 20th December

One of the most common questions we get asked throughout the year is "how do you ring the ospreys?"

If you're new to DOP or just want to see Merin, Celyn and Brening being ringed again, this is the video of the 2015 event.

The whole process is done under license and takes around 50 minutes.

The youngsters keep very still as this is their main form of defence if a real predator were around. Their attempted camouflage pose helps us too and makes the whole ringing process a lot calmer, for us and the birds! 

You can read more about the 2015 ringing here including how we choose the youngster's names. 

ADVENT: 19th December

One of the most loved and charismatic of the Dyfi ospreys is Dai Dot.

We first spotted him in 2010/11 and despite brief liaisons with Blue 24 over the years, he finally managed to breed successfully in 2014 and 2015 at a nest Llyn Clywedog, mid Wales.

He was displaced from his nest soon after arriving back in 2015 by another unringed male and a few days later we spotted him at Cors Dyfi - that was the last time we positively identified him.

There's no reason to think that he has come to grief, he may well be out there somewhere. But here's the problem with unringed birds - they are extremely difficult (near impossible) to ID as individuals. We know him as Dai Dot and can recognise him by his feather patterns and iris dots, but who else would know this information? He would really need to land on another nest with HD cameras like the Glaslyn for us to be able to have a stab at identifying him.

Dai and Monty have formed a friendly relationship, they clearly knew each other from the very early days. Monty would certainly know whether Dai has been around for the last two seasons or not, ospreys recognise each other from huge distances away - problem is, he ain't telling.

We have a wish-list of ospreys we'd like to see again in 2018 and Dai Dot is up there near the top. If we spot him, you'll be the first to know.

ADVENT: 18th December

Glesni produced her first three chick brood in 2015 during her third year of breeding. This was Monty's second time of raising three chicks to fledging age since Einion, Dulas and Leri back in 2011.

The average fledglings-per-nest/year in a normalised osprey population (like Scotland) is just over one per nest. In Wales this average is around two fledglings-per-nest as birds that breed in very small colonies benefit from a reduction in competition for food/nests/mates/resources that their counterparts in larger populations experience.

So when we have three eggs, three chicks, three fledglings, we are extremely happy!

Thanks to the help of Dr. Helen, Ilze and the kind folks at the genetics department, Aberystwyth University, we now know that we had two boys and a girl in 2015, Merin and Brenig being brothers.

The Christmas Day Blog this year will be another instalment in the genetics series but this time written by us. We'll discuss the reasons why we're doing this work, discuss a few hypotheses we have and endeavour to explain what we eventually hope to get out of all this research.

It also looks like Eitha's DNA sample has been successfully assayed the second time around. We'll let you know her result too, if it is a 'her'!

ADVENT: 17th December

After Clarach and Cerist in 2013, Gwynant and Deri were two completely different characters in 2014.

Gwynant was the independent type, slowly getting on with his business. Deri on the other hand was one of the most vocal, needy and loudest ospreys we've ever heard!

Back in 2010 we saw our first Welsh born osprey land on the Dyfi nest as an adult - a two-year-old male, White YC. He was the middle chick of the 2008 Glaslyn brood and we would see him several times again the following season; he would eventually settle in Cumbria and has been breeding there ever since (2014, 2016 & 2017).

On 15th August 2014, we saw our second Welsh born osprey land as an adult - Blue 80. He was another Glaslyn (2012) male having returned as a two-year-old, prospecting his natal areas for a suitable nesting site.

Blue 80 returned the following year and had a brief liaison with his own mother at the start of the season. She was looking for a new male after her long-term mate, Ochre 11(98), failed to return for his 12th successive breeding season. Ochre 11(98) was Blue 80's dad.

After a week or so, Blue 80 was displaced by another bird that we'd also seen land on the Dyfi nest the previous year, a Scottish born ringed male - Blue CU2 (we named him Jimmy!)

Jimmy, in turn, was replaced by the current breeding male, Aran (unringed), but sadly Jimmy was to meet a tragic end, being electrocuted near an electricity pole 20 miles away.

We don't really know what happened to Blue 80 after the last confirmed sighting in 2015, but we have some tenuous information that he may is still around.
Deri would be three years old this year and Blue 80 five.

Here they are on the Dyfi's ash tree perch back in August 2014; wouldn't it be lovely if these two got it together again?

What a story that would make!

ADVENT: 16th December

Here's Gwynant being ringed in 2014. He was Glesni's first male offspring.

Birth sex ratios in birds have been poorly understood over time. One of the main reasons for this is the lack of data, something here at DOP we are thankfully not lacking.

It would make evolutionary sense for a female of any species to be able to produce a higher number of females, or males, at any given time, dependent on the ecological surroundings. The selective pressures on a female of any species to be able to do this would be huge.

For example, ospreys producing more males in an un-naturally small population would be advantageous. For a species with a higher adult mortality rate of females than males, it would make more sense to produce more females at birth to compensate for this.

This begs the question though: the egg laying female would somehow have to have a spacial understanding of the prevailing state of the population to be able to 'decide' which, if any, gender to produce more of.

Ecologists have been talking about 'Sex Allocation Theory" for decades, and it's usefulness in predicting sex ratios. However, it is still not properly understood and a lot more research needs to be done in this area for a greater understanding of the subject. There's a PhD in here for sure!

For the record, the current birth sex ratios at the Dyfi are exactly 50:50 (eight males, eight females).

The picture is practically the same for the whole Welsh osprey population, 50:50.

ADVENT: 15th December

Once Glesni had regained her nest back from Blue 24 in 2014, she soon got down to normal business and eventually went on to raise two more chicks that year, including her first son, Gwynant.

Glesni was a fairly young when she first bred: three-years old, as was her Auntie, Nora.

Average age of breeding for ospreys is four to five-years old although exceptionally, we have recorded UK ospreys breeding at two years old.
Blue 24 has not been so lucky, she will be eight-years old next summer. At least she's found a bachelor male now, let's hope it all works out for them.

ADVENT: 14th December

In early April 2014, planning and organisation for the grand opening of the 360 Observatory had been going really well. Events 200m away at the nest, however, were not.

Blue 24 had been back a whole week (31st March) and had taken over the nest with Dai Dot being the new Dyfi male elect.

Monty returned on 8th April and quickly sent his rival on his way. So started a rather uneasy partnership with Blue 24 - would Glesni return? It would only be her second year with Monty after all, maybe she decided to go and find another nest and mate?

Sure enough Glesni (finally) turned up two days later on 10th April.
What happened next was so interesting to watch right in front of our eyes. It was also some of the most painful few days we've witnesses at DOP. We could barely watch.

With Blue 24 having an 11 day start, fully recovered from her long migration back and having set up home with Monty on the nest, Glesni was at a severe disadvantage.

How much desire did she have to win her nest back? How strong was she having only just flown 3,000 miles to get here.

It took a whole week and three huge attempts, at one point it looked as if one of the fighting females had sustained life-threatening injuries.

At the third attempt Glesni finally usurped her cousin and regained her previous year's nest and mate.

ADVENT: 13th December

We are having our volunteer Christmas party and they all wanted to thank you all for your great support and, many times, friendships over the last 12 months, as well as wishing you a Merry Christmas of course!

Thanks also to all of you that play the lottery here in the UK - you can see what difference it has made to thousands of people's lives here at DOP.
We are still working with Cronfa Dreftadaeth y Loteri - Cymru / Heritage Lottery Fund - Wales on our next project.

If you think the 360 Observatory is good...

Read Emyr MWT's latest blog entries.