Will Miles's association with St Kilda started in 2007 when he began research into the predator-prey dynamics between Great Skuas and Leach's Storm Petrels. During three seasons on the island, he put it firmly back on the birding map, with discoveries of what was Britain's third Blackburnian Warbler and the Outer Hebrides's first Pallas's Grasshopper Warbler in 2009 – only two of the multiple stellar finds that he racked up during this period.
His love for the archipelago has seen him return frequently since his research ended, both to assist National Trust for Scotland staff with seabird monitoring and also to help with end-of-season tasks and to maintain biological recording efforts through the autumn migration period.
Since I started on St Kilda in 2021, we've been fortunate to welcome Will back every year to help out. His knowledge of the island, extensive experience in bird identification, dogged determination to keep searching and of course his company during the quieter part of the season mean that we always look forward to his return and really value his help and support.
Swainson's Thrush, St Kilda, Outer Hebrides (Will Miles).
Back on the island
With all that being said, I was looking forward to his arrival on 10 September this year. As is usually the case upon his arrival, there's an hour or two of him settling in and buzzing about being back before taking a first look around to see what might already be here. We set off together on one of our favoured routes around Ruiaval and up over Mullach Sgar, where in recent years we've had various rarities such as Buff-breasted Sandpiper and Buff-bellied Pipit and where historically there have been megas as remarkable as Upland Sandpiper and White's Thrush.
The excitement and enthusiasm that Will brings each season is inspiring. As we were approaching Ruiaval gully, we were chatting about some of these historical finds and how there are seemingly endless possibilities of what might turn up here.
Upon reaching the gully, a small flock of around 10 Meadow Pipits flushed up, as well as another bird of similar size which caught my eye. I was unable to get much on it at first glance except noting that it had an obviously pale, clean belly and plain greyish-brown upperparts – quite different from the pipits it was associated with.
Swainson's Thrush, St Kilda, Outer Hebrides (Craig Nisbet).
North American rarity
Our minds began racing and we both knew we had to follow it up the gully for another look. A brief second glance at the bird facing us gave us a good look at a distinctive bib of black spots around the breast that immediately recalled a Catharus thrush. At this point the adrenaline kicked in, which was just as well, as clambering up and down Ruiaval gully is steep and hard on the legs, unless of course there's a potential mega to pin down!
The bird had flown further up the gully, so we both slogged our way upwards where we managed to obtain our first record shots, before it flushed all the way back down to the bottom end again. The bird seemed quite comfortable in this gully, so Will followed it back down while I remained higher up, with us both keen to capture images that would clinch identification.
A few moments later, Will was back on the radio with the words "It's a Swainson's Thrush!", having managed to get good shots showing a distinctive buff-tinged eyering which ruled out Grey-cheeked Thrush, the only other real contender by this stage.
Swainson's Thrush, St Kilda, Outer Hebrides (Craig Nisbet).
Catharus confirmed
The bird continued its activity up and down the gully, with us both getting great views at rest and in flight, and some reasonable record shots, before Will managed to capture the photo which essentially confirmed what we could barely believe – we had in front of us St Kilda's first Swainson's Thrush!
The only other Catharus thrush on St Kilda was back in 1965, when a Grey-cheeked was caught on 29 October and was later found dead on the island. At county level, this was only the sixth time Swainson's had been recorded in the Outer Hebrides. It was also the earliest autumn record for Britain, beating the previous earliest by five days.
It was an unbelievable bird to stumble upon within a few hours of Will’s arrival, marking a great start to his trip and a fantastic addition to the St Kilda list, of which there have been six so far this year. The Swainson’s was also the sixth of seven Nearctic vagrants on St Kilda in 2024, and with late September and early October still to come at time of writing, this discovery only reinforced what Will and I know only too well: anything is possible on St Kilda!
