Thursday, 3 October 2024

Sooty shearwater passage and a few eagles, Barra


Barra isn't only about rarities, thankfully. There's also plenty of resident birds to keep you entertained if the rares don't show up, as is the case at the moment. Today we saw four eagles, three white-tailed and a single golden, male hen harrier and three great northern divers. The white-tailed eagles in particular can be very obliging and are often seen well. The bird in the photos flew low over the church at Eoligarry.


White-tailed eagles have proportionally long necks when compared to golden eagles, which gives them a very different jizz, but to be honest there's not really much chance of confusing the two, with white-tailed appearing much larger.



One of the reasons I love this island is that you get to experience some impressive passage. Barnacle geese and whooper swans are yet to come, hopefully next week, and we also get other species that you might not expect arriving from over the sea, such as flocks of snipe. Highlight of the day today was the passage of sooty shearwaters which went down the east coast of the island, heading south in their hundreds. 508 in total were logged, one of the highest counts ever. Although I've seen sooty shearwaters many times before, I've never experienced anything quite like this.


This video is a very short zoomed in section of the previous video. Three birds arc across the screen and are obviously shearwaters. I noticed straight away that at least one of them had a large amount of white on its belly, but which species? Manx is the obvious answer, yet nine days later we discovered that there was a flock of over 1000 great shearwaters between Barra and Coll when only single figures of Manx were seen. So could these be great shearwaters? Well, the first thing is, from the video I would say that they look big and long winged. Difficult to judge though because they were so far out. I recorded the original video on 60x optical through the scope and 2x digital on the phone, so a combined magnification of 120x. These birds were probably around 3.5km distant (2 miles). 


This is about the clearest screen grab I can get from the video. The original was at 120x, this has been cropped to within an inch of it's life! At a rough estimate I would say that this must be around at least 300x magnification and any attempt at identification must bear this in mind. Yet clearly it's a shearwater from the flight action in the video, clearly it has a white belly and underwing, it appears to have dark undertail coverts and may even have a dark neck patch. I wouldn't claim this as a great shearwater had we not seen them from the ferry a few days later on 12th October, yet it's obvious to me that it most probably is one.


Meanwhile the other two birds in the group appear to have dark caps and at least some white in the tail. Even the primaries look darker than the rest of the wing. These are not sooty shearwaters and dark caps and white in the tail only point in one direction and it certainly isn't Manx.


Ultimately I didn't see these birds in the field, I only noticed them from very poor video grabs, so I was never going to tick them and even now it would be ridiculous to claim them as anything more than possible great shearwater. But actually, we all know what they most probably are, especially armed as we are now with the knowledge that there was a large flock of great shearwaters off Barra at the same time.




Eoligarry church, home to many a rarity in the past, most notably American redstart. A little bunting was seen here this morning, but not seen by us.



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