A Pacific Diver in Wales 15th January 2022

During the week I had been chatting to my twitching buddy Mark (R) and we discussed going to see a Pacific Diver which is a very rare visitor to Britain. It hails from the other side of the Atlantic where it is known as the Pacific Loon and breeds on tundra lakes, mainly in northern Canada and eastern Siberia and spends the winter off the Pacific coast of North America and also on large lakes in China, Japan, North and South Korea, the USA and Mexico.They have also been recorded as vagrants in Greenland, Hong Kong, Great Britain, Ireland, Spain, Finland and Switzerland.

Pacific Divers were once considered conspecific with our native Black throated Diver and only split from that species in 1985, based on mitochondrial DNA analysis. They are a very rare species in Britain.To date there are only nine accepted records in Britain and four in Ireland.

The individual we wanted to see was a juvenile that had decided to spend its winter days on the Eglwys Nunydd reservoir, where it was first discovered on the 11th December 2021.  The 260 acre, 4.3m deep reservoir lies right by the M4 Motorway at Margam which is close to Port Talbot and supplies water to the adjacent and huge Margam Steel Works owned by Tata Steel.

The one big problem with viewing the diver is that the reservoir is closed to the public, including birders, due to the presence of an invasive 'killer' shrimp that attacks and kills our native freshwater shrimps. I kid you not. To no little controversy the Welsh Environment Agency closed the reservoir to the public on bio security grounds to try and stop the spread of the shrimp but the local angling club and yacht club are still allowed to use it, so all in all the closure seems perverse. There are rather lax security patrols but if they are avoided it is possible to bird the reservoir and many local birders seem to cope by avoiding the infrequent patrols. At first I found this prospect daunting but as the weeks passed it became apparent that after an initial flurry the security patrols were very few and far between and there was not likely to be a problem.

Birders are ever resourceful and despite locked gates there are at least two different 'off piste' ways to access the reservoir, details of which I will not divulge here but one of which we took advantage of, courtesy of a local birder.

Mark and myself made plans to go to Margam and decided Saturday would be a good time to go and try our luck. Mark would drive from his home in Bedfordshire with two friends, Les and Andrew while I would drive separately from my home in Oxfordshire and meet them near to the reservoir. We decided to meet up at first light and make our way onto the reservoir and hopefully get our fill of the diver. The reason for an early start was that it was highly unlikely that there  would   be any security around early on a Saturday morning and as we planned to park in a cemetry, we did not wish to impinge on anyone coming to pay their respects to departed loved ones.

Friday's weather was predicted to change overnight  but still remain below freezing and as I left  home at 5am and made my way over The Cotswolds to reach the M5 and then M4 motorways that would take me to Margam, I was confronted with not only frost and icy roads but freezing fog. It was a nightmare to drive in such conditions  but I had plenty of time as I was about an hour or more ahead of Mark, Les and Andrew. 

Once on the M5 motorway I set the cruise control to fifty and 'dawdled' along on the inside lane, experiencing the novelty of being overtaken by huge trucks when the reverse is usually the case. I  reached Bristol and diverted onto the M4 and was soon heading over the huge Severn Bridge and into Wales. A couple of stops for coffee at some services along the way whiled away more spare time. I called Mark to find they were now scheduled to arrive about thirty minutes after me at our rendezvous point. I arrived at the cemetry just after dawn and parked my car in a discrete corner. I was the only person present. Well, living anyway! The reservoir and the cemetry were adjacent to the motorway so there was little problem in finding both.

I called Mark again to find they too had visited a motorway services but had managed to get back on the motorway heading in the wrong direction! You may laugh but I can speak from experience when I say it is easily done, as the signage in many motorway services is truly appalling, the exit arrows worn to nothing by countless cars passing over them and rarely reconstituted, while the exit route is often convoluted and confusing, which all adds to the burden of trying to think straight after a long wearisome drive in the middle of the night.  

Today, in marked contrast to yesterday, the sun was going to be a stranger and there would be constant cloud but not thick enough to be gloomy, A cold southeast wind was also beginning to make its presence felt as I stood outside my car surveying row upon row of remarkably similar but well tended grave stones, in the dull light of early morning. An involuntary shudder passed through me which might not have been from the cold wind.

I soon cheered up when Mark arrived.Getting everything together we set off on the secret route to the reservoir.I led the way as I had been here on Monday with Clackers but such were the obstacles confronting us to get onto the reservoir and Clackers comparative lack of mobility we aborted our attempt to gain access, as it required an amount of physical effort that would be too much for the Clackmeister.

This time we successfully negotiated all the obstacles we came up against. No one fell in the thick wet mud we had to negotiate and we crossed a deep culvert without mishap. Before us lay the grassy reservoir bank and the northwest corner of the reservoir which coveniently was the preferred location of the diver.

View from the northwest corner of Eglwys Nunydd reservoir

Sure enough, on getting to the top of the bank, there was the Pacific Diver, the third that I have seen in Britain, swimming and diving a little way from the bank. The images that have been published over the prior weeks indicated it could come very close but at the moment it seemed disinclined to do so.Mark sensibly suggested it was probably a little alarmed about our sudden arrival on the perimeter track on the top of the reservoir as it could see us silhouetted against the sky and we should drop down under the retaining wall where we would be less obvious. 

We followed this eminently sensible suggestion and by means of some handy brick steps we all duly got down below the wall. As if by magic the diver came ever closer and eventually it was at point blank range, diving and surfacing right in front of us. We stayed put and were treated to a bravura performance by the diver. It was hard to contain our excitement as we clicked away with our cameras and let out gasps of pleasure as yet another frame filler was achieved. None of us could have wanted better, it was just incredible how close the diver came to us as we watched it. 

From what I could see it was feeding on tiny fish, possibly sticklebacks,which was in marked contrast to its larger cousin, the Great Northern Diver at my local Farmoor Reservoir, which had been eating much larger fish.It also had the curious habit of vigorously waggling its tail in the water just after it had surfaced, causing a minor turbulence. It did this repeatedly so maybe this is a particular habit of the species or possibly just this individual. I have never seen such a thing with other divers. Who knows? 

There are always questions.

Overall it was smaller and sleeker than the other two small divers, Red throated and Black throated.  I am told they can also vary in size individually. Generally it appeared a neat, compact bird with a short, slender bill, bulbous rear neck, and round head giving a subtly different profile to the other two small diver species (Red and Black throated) found here in Britain. When facing us there was the faintest hint of an indistinct brown line across the front of its neck where it met its breast, a diagnostic character of a Pacific Diver if present but the complete lack of a bulging white thigh patch was the main diagnostic feature to separate it from a Black throated Diver. 

It was a juvenile, told by the symmetrical patterning of scaly fringed feathers on its upperparts.

As with the diver at Farmoor, when it had ceased feeding it swam further offshore and loafed, preened or even briefly slept, before, after ten or fifteeen minutes, it would return to its favoured northwest corner of the reservoir to feed.

For an hour and a half we watched, enthralled as it swam and dived. Surfacing with a start, as if taken by surprise, it was immediately alert, in case anything might have changed while it was underwater.Then it would quickly settle and float around for a minute or two before diving once more

A tap on my head came from above. 

Hello!

I looked up and there were Paul and Vicky, two fellow Oxonbirders. A real surprise and a pleasure to see them. They came and sat with us below the wall

The diver was at this moment somewhat distant but soon enough they too had the diver up close and personal and everyone was happy.

A bit of birding banter, a wander along the perimeter track to view a distant Ring necked Duck and then it was mutually agreed that we had all reached that point of satisfaction where it was time to leave. We retraced the route we had come by and returned to the cemetry car park.  

There is no better feeling than a successful twitch with like minded people and who are, above all else friends.