Thank you both. It was pure luck. We couldn't believe our eyes either. We do get them regularly in spring, at least in some parts of Italy, but we certainly weren't expecting to see one in the Hebrides!
So far we have had a fantastic time, with highlights being Forvie Sands, Cairngorm mountain, Dunnet Head, Handa island and yesterday on the Uists (full report when we get back home).
We haven't had much luck with eagles so far, only distant views of both species, and we are still missing Redpoll, Bullfinch and Twite, but have hopes for the first two when we get back on the mainland on Friday (Skye, then Fort William, then Pitlochry). As for eagles we are joining a guided RSPB walk at Loch Druidibeg on Thursday. Fingers crossed!
Anyway a total of 117 species so far, plus various mammals, so not bad at all!