Tuesday, 12 July 2011

In-flight entertainment

We began the 8.2km crossing to Boreray, a crossing of open Atlantic water.  There was a large swell running but otherwise conditions were good.  The oceanic swell was a joy to paddle, great slopes of water passing beneath us.  The crossing took around two hours as we had some tidal movement to contend with - in the St Kilda archipelago there's also ocean current to factor in. 

To keep us on course we used the best transit any of us could imagine, keeping the top of Stac Lee in line with the summit of Boreray.  Carlsberg don't make transits, but if they did........

Our in-flight entertainment all the way across was provided by the birds, Gannets and Great Skuas (Bonxies).  There are well in excess of 50,000 pairs of Northern Gannets (Sula bassana) in St Kilda, most of them on Boreray and the stacs.  The sky was simply full of them, wheeling and swirling around us.

Ganets have a metre long body and a wingspan of about two metres.  They are fish eaters and hunt by making spectacular plunging dives from about 10 metres up, folding their wings and powering into the water.  They can swim well underwater.

A Gannet's skull has air chambers to withstand the shock of repeatedly diving into the sea, they are supremely adapted to the sea.  Young birds spend three years at sea before returning to breed, and outside the breeding season the colonies disperse to mid Atlantic and equatorial waters.  They are very handsome birds, snow white plumage with black wingtips, a golden head and a bright blue eye.

The Gannets we were seeing flying directly towards Boreray undoubtedly had a full cargo of fish in stomach and crop for their hungry chicks.  They may have hunted up to 200km from the nest, so it must be galling in the extreme to get "bounced" by the piratical Bonxies within sight of their nests.  Several Bonxies will harry a Gannet, twisting and chasing but always forcing it down toward the sea.  Sometimes the Bonxies will grab tail feathers or (more seriously) a wing joint and flip the Gannet in mid-air.  We watched dozens of these chases, and most resulted in the Gannet regurgitating some of it's fish to stave off the attack.  None of the fish ever hit the water before the Bonxies caught them.  Sometimes a Gannet would evade the attack, but most often the Bonxies got their fish.  It was fascinating stuff.

Cuma had gone on ahead to film around Stac Lee.  We watched her almost disappear below Boreray, and even when we were much closer the size of the swell hid her completely at times.  Long crossings have never really been my thing, I prefer the interaction of land and sea and to explore coastlines. This, however, was fantastic, committing paddling at it's very best. 

We already knew that we'd not be able to circumnavigate Boreray as the weather was closing in, the signs of an approaching front clear in the sky to the west.  We still had an absolute highlight to come though.

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