If the early-season drama at Dyfi with Blue N0 taught us anything this year, it is that our airspace is getting wonderfully crowded.

When we look back at the 2026 season, one trend stands head and shoulders above the rest: we have recorded the highest number of osprey intruders to date, both here at the Dyfi nest and across other nests throughout Wales.

Two intruders at the same time at the Dyfi - 5^th August 2026: 𝐁𝐥𝐮𝐞 𝟔𝐂𝟔 - Cumbria female (2022) and 𝐁𝐥𝐮𝐞 𝟕𝟐𝟏 - Tweed Valley Male (2022)

The Numbers Game: What the Data Shows

Across public and semi-public nests in Wales this season, a remarkable procession of ringed visitors dropped in to test boundaries, check out real estate, or occasionally ruffle some feathers. Literally.

• At Dyfi alone, we logged 12 distinct ringed intruders over the course of the spring and summer - a new record.
• Across other Welsh nests (including Glaslyn, Llyn Brenig, Clywedog, Pont Croesor, and the Usk Valley), an even larger wave of ringed nomads was sighted making their presence felt.

Yet, these figures only tell part of the story. There will undoubtedly be more in reality. 

These numbers represent strictly the birds we can identify—the ringed individuals whose histories we can trace back to Cumbria, Scotland, or other Welsh strongholds. Furthermore, this data completely excludes the many unringed birds that visit, remaining entirely anonymous as they scout out prospective territories.

Most of these are probably Scottish birds, as less than half of the osprey population north of the border are ringed.

Here is the full list of identified ringed ospreys both at the Dyfi and a few other Welsh nests that are monitored:

Patterns in the Skies

Analysing where and when these intruders appear reveals some fascinating patterns:

41 Unique Birds in Wales as a whole and 12 of these birds at the Dyfi nest, beating last year's record of 11. Excitingly, out of the 41 unique birds, two are brand-new chicks born this year:

• 9L8 (Male): Born in Mid Wales at a private Dyfi nest (the eldest of two chicks).
• 3B9 (Male): Born in Kielder, England (named Kirknewton).

More birds each year mean just one thing - ospreys on the whole are increasing in numbers. We're slowly transitioning in Wales from a Recovery Population Status to one of low density.

Some of these birds on this list will undoubtedly be breeding in Wales in the future - either at brand new nests or by having replaced non-returning birds.

You can spot direct genetic connections between birds on both lists by looking at their parents:

• The Glaslyn Dynasty: Intruders 0H1 and 6M9 (on the Dyfi sheet) along with 0H2 (on the other nests sheet) are full siblings. They all share the exact same famous parents: the unringed male Aran and unringed female Elen from the Glaslyn nest.

• The Tweed Valley Connection: Intruders 721 (seen on both lists) and 6J8 (seen on the other nests list) are also full siblings. Their father is the BTO-ringed Oscar and their mother is FS2.

  
  Calculating the ages based on the "Born" column highlights a clear trend in osprey behavior:
   

  • The Hatchlings (2026): 9L8 and 3B9 were born this very year.
  • The Sub-Adult "Sweet Spot" (2–4 years old): The overwhelming majority of the birds on these lists were born between 2022 and 2024. Ospreys typically do not breed until they are 3 to 5 years old (although we had a two-year-old breeding on Anglesey this year!).
    These 2, 3, and 4-year-old birds are in their prime wandering years, scouting out potential future nest sites and partners.

Where Are They Coming From?

While many intruders are Welsh-born (6 out of 12 at the Dyfi and 12 out of 30 at the other nests), just over 50% are travellers from outside Wales who are looking to expand their range:

• The Scottish Contingent: Birds like 721 and 6J8 from the Tweed Valley, 4B9 from Threave Castle, and veteran PE from Moray show a heavy flow of Scottish ospreys.
• The English Contingent: Ospreys are filtering into Wales from all over England, including Cumbria, the Lake District, Kielder, Rutland Water, Foulshaw Moss, and even as far south as Poole Harbour (5R0).

The intruder population shows a very even balance between the sexes, with a slight edge toward the males:

• Males (M): 19 unique birds (56%)
• Females (F): 15 unique birds (44%)

This is exactly what we'd expect, females are always under-recorded.

From One Pair to Twenty: A Conservation Triumph
 

Why are we seeing so many more osprey intruders recently? Quite simply, it's an ecological barometer of a thriving population.

When ospreys first returned to Wales 22 years ago after several centuries of localised extinction, that pioneering pair was a precious anomaly—a solitary pair that nobody at the time knew would either just fizzle out or be the conservation foundation for much greater things to come. Today, following two decades of painstaking conservation, legal protection, and natural expansion, Wales is up to around 20 active osprey nests.

When you scale up from a single isolated pair to a healthy network of 20 nests distributed across Wales, the number of roaming, non-breeding sub-adults looking for a place to settle multiplies exponentially. 

An "intruder problem" is, paradoxically, the best possible problem a conservation project can have. It means the species is resilient, ecologocally confident, and overflowing the boundaries of its historical strongholds. This is classic breeding dispersal in action.

I remember seeing a ringed intruder osprey on the Glaslyn nest in 2005 - it was literally a Press Release event (no social media back then!). Today, thankfully, it's a very common occurrence. 

White 03 - a 2011 visitor to the Dyfi nest. A second-generation Rutland Water translocation bird. I named her Nora.

As autumn brings relative quiet to Cors Dyfi and our osprey family are on their way south, we can look back at 2026 not just as a vintage year for breeding success, but as the year the Welsh osprey population truly came of age. The skies are busier than ever - and dare I say it - the osprey population in Wales has now, most probably, reached escape velocity.

By that I mean a bad flood, an extreme weather event or any other force majeure incident, like as we saw in Brenig in 2021, is unlikely to cause significant risk to the Welsh colony on the whole.

In Wales, we stand on the shoulders of those that helped us, decades ago. 

Roy Dennis up in Scotland and Dr. Tim Mackrill in particular, plus Leicestershire Wildlife Trust. Their pioneering translocation project in the 90s eventually led to ospreys recolonising Wales - both at the first successful nest near Welshpool in 2004 and the Glaslyn nest 2005 and onwards. 

That project also gave us Nora, Glesni and Telyn here at the Dyfi. We would not be where without them.

Twenty years of ospreys in Wales have led to 20 nests. What will the next 20 years bring...?

Ochre 11 in Wales in 2005; born in Scotland in 1998 and translocated to Rutland Water at five weeks old.