Blogs are a great way to keep up to date with the goings on at other seabird colonies and I try to browse through my 'favourites' on a regular basis. A few days ago I was looking at the Skokholm site and noticed that St Kilda had a mention as, on the 4 April, the Rangers spotted one of 'our' great skuas on the island.
(photo: Richard Brown, Skokholm Blog)
How did they know it was from St Kilda? Well, once the bird moved they saw it had colour rings on its legs; a white ring on the left leg and a pale blue ring above a white ring on its right. As all colour ring projects are registered it only took a wee while to discover that the bird was caught on the main island of Hirta as part of Will Miles' PhD research in the late 2000s. Each bird that Will caught was given a unique four colour combination of rings. The technique of colour ringing is a great way of monitoring the behavior and movement of birds because, besides the initial capture event, it involves minimal stress and interaction as the rings should be highly visible from a distance.
(Photo: Richard Brown, Skokholm Blog)
Did you notice that I mentioned Will applied four colour rings to the birds he captured and that the photograph above shows only three? The rings can remain attached for decades but sometimes they will fall off, slip inside one another or the colours fade over time. Will thinks that there are two white rings on the left leg and that they have overlapped, this explains why the white looks quite big, broad and somewhat sectioned. If this is the combination then we know the bird was caught in May 2007. We also know that the rings have been like this since at least 2012 as I have a photo showing the same slipped ring combination.
The Bonxie stayed at Skokholm for a while where it enjoyed a meal of rabbit before being spotted elsewhere annoying Lesser Black-backed Gulls. Hope it doesn't get a taste for bugs bunny because if it comes back this year it certainly won't find any out here!