In the table below you will find details of all Welsh osprey chicks that have fledged since 2004 when ospreys again started to breed here after an absence of many centuries.
Here are a few things to bear in mind:
- All the chicks have been ringed and weighed - there are 64 in all. The ring colours are represented by the actual colours used in the table (bottom).
- Not all the nests are monitored 24hrs a day so therefore it's not possible to know the exact dates for some key events like age at ringing and fledging.
- In all, there have been five active nests in Wales, we've numbered them ON1, ON2 etc, ON meaning osprey nest. They are numbered in chronological order, so the higher the number, the more recent the nest is. ON4 and ON5, the most recent, are not in the public domain so are not called by their place names like the Glaslyn and Dyfi nests for example. See below the table for the ON nomenclature.
- The gender of each chick is established when the bird is around four of five weeks old when they are ringed. Weight, wing length, leg girth and general 'feel' of the bird to the ringer are all taken into account, but this is only a guess at the end of the day. Sexing young ospreys is not an exact science and is approximately 90% accurate.
- To date, 61 ospreys have fledged Welsh nests; 30 males and 31 females. Of these, eight birds have been spotted as having returned to the UK, six from the Glaslyn nest, one (Clarach) from the Dyfi nest and one from the the ON4 nest - Blue 9R. Five of the six Glaslyn returnees are, or have, bred successfully themselves. They are:
- Yellow 37 - breeding at Kielder Water, Northumberland, England.
- White YA - breeding at Kielder Water, Northumberland, England.
- Black 80 - breeding at Dumfries and Galloway, Scotland.
- White YC - breeding in Cumbria, England.
- White 91 - breeding in Perthshire, Scotland.
White YC in Cumbria, 2016 (this is the Foulshaw Moss nest, he actually breeds a short distance away on the Roudsea Moss nest).
The other three Welsh (offspring) ospreys re-sighted in the UK but not breeding are:
1. Glaslyn 2012 male, Blue 80. He's been spotted at the Dyfi nest in 2014 as a two year old, and at his ancestral Glaslyn nest in 2015 where he actually bonded with the female there (his own mother) for a few days before being displaced by another male.
2. Dyfi 2013 female, Blue 2R - Clarach
3. ON4 2014 female, Blue 9R. Spotted as a two-year-old in 2016 in Kent (May), County Fermanagh (June) and Ogston in Derbyshire (July)
Blue 9R respotted as a two-year-old adult in 2016
Glaslyn's Blue 80 lands on the Dyfi nest next to Deri, a 2014 fledgling:
BREAKING NEWS - 3rd MAY 2016: CLARACH IS BACK IN WALES AS AN ADULT - Blog here
By 29th May, 2016, Clarach had made it all the way to Kielder Water in Northumberland
The key facts so far from 2004 to 2016:
- Number of known Welsh nests to date : 5
- Number (cumulative) of individual breeding birds at those nests: 13
- Number of those 13 that are/were ringed: 4 (31%)
- Number of chicks hatched: 70
- Number of chicks fledged: 61
- Number of chicks re-spotted as returned to the UK as adults: 8
- Number of those Welsh offspring breeding as adults: 5
If you're up on your osprey ecology and know that ospreys, males in particular, are highly philopatric (return to their ancestral colony to breed themselves), you may well be wondering why on earth all five of these Glaslyn offspring have nested so far away from Wales?
Here's the deal: philopatry works in a normalised osprey population, or one that's nearing being normal at least. When the five birds above returned as two and three-year-olds, there was only one pair of ospreys in the whole of Wales - their own ancestral nest. With both their parents back each year, they had little chance of finding other ospreys in the area so they would have had little choice but to move on to somewhere else. True, they could have built their own nest close by, but they chose not to. Like many large birds of prey, ospreys much prefer to inherit or steal nests (by displacing other, weaker birds) than build their own.
The five Glaslyn offspring chose not to nest close to their ancestral nest
There's a classic case of osprey philopatric breeding-dispersal dynamics at the Rutland Water colony right now. Out of the seven or so breeding males there, every single one of them is a Rutland offspring and these birds have never been spotted elsewhere. In fact, to date, not one Rutland born male (out of 50+ over the years) has ever been spotted back in the UK anywhere other than Rutland, or very near to it. Classic philopatric osprey ecology in action.
The osprey 'colony' in Wales is much healthier now at four nests, but it is still a species very much in recovery. There's no doubt that we will start to see Welsh males return (and stay) near their ancestral nests in the future, it's a waiting game and one that's not been made any easier by having a glut of females in the last few years!
A youthful looking Tony Cross doesn't quite have the height to ring the first Welsh osprey chick back in June 2004 at ON 1, Welshpool. All other Welsh chicks since have been ringed.
Here's the table (with thanks to Heather Corfield for compiling):