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The Antarctic skua

1/ What are skuas like?


The Antarctic skua (Catharacta maccormicki) is the size of a largish gull. They nest all around continental Antarctica and breed into the deep south. They are excellent fliers and have occasionally been sighted deep in the interior hundreds of miles from anything other than ice. One of their feeding techniques is to chase and bully other birds into regurgitating the contents of their crop, a strategy successful with some species that are in themselves excellent fliers. They tend to have a reputation as being fierce and aggressive birds, which is somewhat unfair. I see them more as characters who stick up for their own corner and look after their own - no more or less than humans do.
Often a visitors first sight of a skua is at a penguin colony where they usually are nesting nearby. They hang around as a dark presence looking for unguarded eggs or weak or isolated chicks to prey on, which is a very productive means of finding food, but does their reputations no good at all.

2/ What is this skua doing?


This is a displaying skua. They display to, or for a mate or to other skuas to establish their territory. Sometimes the birds can be seen to do this as a pair, it is quite an impressive sight and the squawking can be heard some considerable distance away. Skuas will also do this if their nest is being approached by an unwanted visitor.  More often though the first sign that a visitor gets of being near to a skuas nest is of a sudden heart-stopping rush of air through the wing feathers of the parent bird flying at speed past your head from behind, much too close for comfort. If you're particularly unlucky or if its very unhappy at you being so close, then rarely a whack at the back of the head by the front of the wing may result. This is actually quite a good way of finding skua chicks - when the parents start getting upset you know you're very close to the excellently camouflaged chick.
This bird however was semi-tame and was calling to his mate to come quick as there may well be some give-away food. The biggest problem I had taking this shot was getting the bird far enough away as he kept sticking his beak about 10cm from my lens.

3/ What are these skuas doing?
These birds are on the specially made skua landing platform (also used by occasional Dominican gulls and sheathbills) outside the kitchen window of the scientific station on Signy island in the South Orkneys. There were two pairs of skuas that used it regularly (never at the same time though), the "Reds" and the "Blues" they lived respectively to the sides of the platform of their colours. This is Mr. and Mrs. Blue. Their nest was about 250m away downhill of this rooftop platform and occasionally when feeling lazy, they would walk up rather than fly and then glide downhill back home. If you were out nearby they would sometimes come to see if they could get any free food (see above) squawking and hovering above you. If you lent over forwards, then sometimes one would land on your back and look quizzically sideways at you as if to say "Now what?". I also had one of them once try to land on my back-pack as I was walking along. Unfortunately it was a purpose made back pack that consisted of a frame with two large open top cans attached. The first I knew what was happening was when Mrs. Blue fell into one and with much scrabbling and panic managed to get out of it before settling nearby and giving me a haughty stare.

4/ What kind of birds are these?
This is a Cape pigeon or Pintado a pigeon sized petrel common around sub Antarctic islands and peninsula. They nest on rocky ledges and usually rear a single chick which looks particularly shape-less until it fledges. It used to remind me of a fluffy ball with a head just stuck on the front. The birds tend to feed in flocks on krill and small fish but also will scavenge on scraps discarded by skuas and giant petrels when feasting on floating seal carcasses.
5/  Are these the same bird?
These are sheathbills (also sometimes referred to as "Mutts" - it just seems appropriate) and they're the "dust men" (garbage disposers) of the Antarctic. They will eat just about anything that they can lay their beaks on, the one in the lower picture had been feeding on (in) a dead seal. They frequently scavenge penguin colonies for eggs, dead chicks, even penguin faeces - there's occasionally some not fully digested food there. The only Antarctic bird species that don't have webbed feet and so are not able to fish for food like the others. They usually stay out of the path of the sea-ice and move north in the winter when the worst weather comes. The top picture however was taken in mid-winter at a temperature of minus 30 centigrade of one of a small colony of sheathbills that lived around the base on Signy island. Whereas most of the other sheathbills would move north, this hardy group evidently thought that there were enough scraps available from the base to make staying worthwhile. Surprisingly hardy creatures, the bird in the picture has its feathers fluffed out as far as it can and is considerably skinnier than this picture shows.
In an attempt to try to reduce heat loss mutts will hop around on one leg rather than risk getting two cold. This made landing rather exciting as they found out the hard way that this is really a two legged activity. Frequent falls down small holes were another hazard as their one leg went between slats on wooden decking. In fact so determined were they to not use both legs and so clumsy in the process, that for a while I was convinced that there were actually several unfortunate individuals that really only had a single leg, as they would hop away rather frenziedly if they were in your path rather than put the other leg down or fly.

6/ Sheathbills - waiting for kitchen scraps
Sheathbills "Mutts" waiting outside the kitchen window in winter. With no skuas around in the winter months, these birds that live around an Antarctic scientific base can actually get to the best supply of food around at this time. They accumulate around meal times drawn to the smells coming from the kitchen waiting for the "gashman" to start clearing up and hopefully throw some tasty morsels in their direction. Not exactly a good looking bird and very nervous and skittish as befits a small and vulnerable creature that makes its living by scavenging, it was difficult not to have some respect at least for Mutts as they braved the harshest of conditions and seemed to know their place in the hierarchy - right down at the bottom.

7/ Why does this bird suddenly dive bomb?


Antarctic terns nest on the Antarctic peninsula and also particularly on antarctic islands. It lays it's eggs in small quite widely spread out colonies, i.e. low density of birds in the colony. The nests are made on the ground in places that tend to be isolated but quite exposed. The eggs and the chicks are excellently camouflaged and the birds defend them from a distance so as not to draw attention to where the nest is.  The upper picture shows a tern hovering at the "nervous" stage when its nest is being approached maybe by a skua or other scavenger. Once the intruder gets too close for comfort then it dive-bombs as in the lower picture. No apologies for a lack of sharpness in this picture, this is exactly what it seems like. The term dives and builds up great speed before letting out an ear-piercing call that is perfectly timed to cause maximum panic and consternation. No matter how prepared you think you are, the first "attack" feels like it's removed some time from your life.
Terns feed on small fish and plankton, such as the ubiquitous krill
 
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