Posted: Thursday 8th August 2013 by Emyr MWT

Dyfi Osprey ringing 2RDyfi Osprey ringing 2R


On Tuesday morning, August 6th, we ringed both our osprey chicks.

On a cloudy but windless day the ringing team approached the nest at around 09:15 and the first thing that took our eye was Monty's second nest. It's huge!!

Lots of thoughts on why Monty is building this new nest - see here

Monty's second home - just above his main nest
Dyfi Osprey Monty's Shed

As expected, Glesni was up in the air as we got close to the nest, calling every few seconds. This communication is targeted directly towards the chicks and is a type of alarm call - directing the young ospreys to hit the deck and play dead. Camouflage is the chicks' only form of defence really at this pre-fledging stage. If there was a real predator around, evolution has given them an excellent avoidance system based on stealth and mimicry.

'Thanatosis'  - a close up view
Dyfi Osprey thanantosis

Bird ringer Tony Cross was with us again this year with the help of fellow ringer Chris Townsend, and as soon as Tony brought the chicks down and took them out of his bag there was a momentary period of silence. Both birds looked absolutely gorgeous - they looked plump, they looked clean and they looked healthy.

Tony started with the first osprey out of the bag and carefully put a small metal BTO (British Trust for Ornithology) ring on the left leg and then a plastic 'Darvic' ring on the right leg. The Darvic was Blue 1R and was placed reading up from the foot as it should be in the UK.

Dyfi Osprey 1R

1R was then gently lowered into a bag for weighing. There are two main ways to assess the gender of a young osprey in the field - the thickness of the tarsi (basically the lower leg) and the overall weight of the bird. This osprey had very thick legs and weighed 1,660g - almost without doubt a female.

Tony weighs Blue 1R, 1.66 Kg - a very healthy weight for a female.
Dyfi Osprey weighing

We then turned to the other chick. This one weighed more than the first one! 2R had equally bulky legs and weighed an impressive 1,710g, the second heaviest osprey to be weighed in Wales (out of 31 chicks since 2005)

Update: Many congratulation to Barbara for winning the Guess the Weights Competition. Barbara didn't guess close, she got it bang on to the nearest gramme!! Combined weight of 3,370g - well done, goodies on the way!

Look at the legs on that!
Dyfi Osprey 2R

Despite not satellite tagging our chicks this year, we still felt it appropriate to name them. Following on from the past protocol of naming our chicks after local rivers, our two females will be called:

1R - Cerist

2R - Clarach

(Pronunciation: Both have a hard C as in Carol and the 'ch' in Clarach is pronounced as in a Scottish Loch. We tested both names out as usual on our volunteer Posh Pete and he came through with flying colours. If Pete can say Cerist and Clarach, everyone can!)

UPDATE: August 16th - Many thanks to Dyfi Osprey Project fan Rhiannon for making this short video of how to pronounce the chicks and Glesni's name. Diolch Rhiannon.

Cerist with her new bling
Dyfi Osprey Cerist

To be honest, it's no surprise that both birds are around the 1.7Kg mark. Good weather has no doubt helped this year, but so too has the quality of the parenting. We know how good a fisher Monty is, but we sometimes forget that Glesni is only three years old herself and is bringing up a family for the very first time. They have both done a great job.

The significance of these weights cannot be understated. By the time they leave for their first migration south in seven or eight week's time, both Cerist and Clarach will have that extra weight (and therefore energy) to keep them going. I have no stats to hand, but I'm convinced that there is a positive correlation between chick weight and return rates a few years later. That is, well nourished youngsters are statistically more likely than leaner birds to survive and return to the UK.

Montgomeryshire Wildlife Trust would like to thank the ringing team again this year. These guys are experts in their field and do all this work for us voluntarily.

Tony Cross - Ringer
Chris Townsend - Ringer
Al Davies - ladder man, elecrician and general dog's body!

And a special thanks to young Justin who, after volunteering at DOP for many years, came to the ringing with us this year for the first time and saw these wonderful birds close-up.

Dyfi Osprey Justin

Here's a video of the ringing condensed to less than five minutes, shot almost exclusively by Justin (with Janine on the nest cams in the office!).

Many thanks to you all for helping us with our work.

I hope that you are reading this, for the second time, in 2015 or 2016 after Cerist or Clarach has just been spotted back in the UK looking for a nest site, to see what she looked like at 5½ weeks old.

Watching in 720 or 1080 is best

Music: Passage by Ludvico Einaudi

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