The Great skua Stercorarius skua is the largest skua in the northern hemisphere, breeding each summer in northern Scotland, Iceland, and the Faeroe Islands. 60% of the global population breed in Scottish colonies, the most significant of which are shown here.
Great skuas (or 'bonxies', a Shetland word meaning dumpy, untidy women) are majestic and powerful seabirds that never fail to provoke a reaction.
At sea, they can often be seen harassing gannets or gulls to make them drop their their food, or following fishing boats to scavenge their discards. But they also hunt other birds: off the cliffs of Handa, we have witnessed bonxies grabbing kittiwakes in mid-flight and taking them down to the ocean to drown them.
From May to September each year, bonxies breed in colonies on coastal moorland. On Handa, nearly 300 pairs of monogamous bonxies hold back-to-back territories among the heather, each territory measuring between 20m and 100 m across. They start breeding at around 5 years old and can rear 1 or 2 chicks each year until they are over 20, probably in the same colony. Generally the older, more experienced parents have the bigger territories.
Breeding bonxies are relentless and ferocious in defence of their territory against human (or any other) intruders, especially when the chicks are young.
On Handa, the only usual victims of this aggression (apart from the occasional otter) are us, the skua researchers.
While we attempt to disturb the birds for as short a time as possible, we visit each territory once a week to check on the progress of the eggs or the chicks, and sometimes to ring the chicks.
There is no getting round it - an occasional whack on the head from the feet of these magnificent birds, sometimes followed up by a well-aimed regurgitation - are an unavoidable part of the job if you want to monitor skuas!
Bonxies on Handa, as throughout their range, are a contentious presence - to read more about bonxie issues, go to the Conservation page.