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Bonxie chicks & Brocken spectres - First impressions from the Petrel-Skua Team

22 June 2007

Will Miles and me are up from the University of Glasgow studying the interactions between bonxies (great skuas) and Leach’s storm petrels.  One of our aims this summer is to find all the nests of the bonxies on Hirta.  When we find a nest we measure the length, breadth and weight of the eggs and from these we can calculate the laying date.  To get an idea of the skuas’ diets, we also look for food remains and, in particular, the birds’ pellets.  Like owls, bonxies cough up the hard parts of prey that they cannot digest.  We can usually tell the prey from the colour, size and shape of these indigestible parts such as feathers, bones and fish otoliths (fishes’ ear bones distinctive to species), or from a good sniff of the pellet!  Fulmars, shearwaters and petrels are eaten by bonxies quite frequently on St Kilda and all have a very distinctive musty smell.


We have been here for over one month and established a routine of working afternoons and evenings on the bonxies and overnight on the petrels.  Part of studying the petrels’ nocturnal activity involves recording the changes in light levels through the night.  Now, at midsummer, it barely gets dark before the light returns again from 2am onwards and only the brightest stars show in the sky.


3 bonxie swoop

Bonxie attack!

Photo © Liz Mackley


Some of the bonxies are very aggressive, especially now the chicks are hatching - you may see us on the time-lapse camera being swooped on or slapped by defensive skuas.  We have five intensive study sites across Hirta which we visit most frequently.  Today I came across squeaking and hatching eggs and newly emerged (but already fluffy brown) chicks tottering about, still a little naïve as they begged me for food. We will follow the fate of these young fluff balls as they sprout feathers, go through their ‘ugly phase’ (!) and finally fledge towards the end of July / August.


2 bonxie chick

Bonxie chick - Cute fluffy phase!

Photo © Liz Mackley


We’re living in the old Feather Store, which is fairly basic by some standards (with no plumbing).  For me, however, lying in bed in the morning looking out over Village Bay and Dun, it is idyllic! St. Kilda, with its high cliffs, hills and numerous islands and stacks, is dramatically beautiful and there are amazing sky and seascapes everyday.  My highlight so far has been a Brocken spectre (see photo), but others have included a female snowy owl, an Iceland gull and being surrounded by fulmars and spotted heath orchids.  Plus, of course, those St. Kilda specialities: big noisy wrens, fat mice and the Soay sheep, the ewes and rams of which are only a few tufts, strips and tassels of wool away from their fresh summer coats, making them look like they’ve attended an experimental poodle parlour!


1 brocken spectre

Brocken spectre on Mullach Mor.

Photo © Liz Mackley


Liz Mackley

Masters student at the University of Glasgow

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