Not unfrequently, indeed, they will kill and devour the bird itself. Graba tells us that he saw one of them at a single blow shatter the skull of a Coulterneb, and various witnesses testify that they eat Sea Gulls and Guillemots, striking them dead with their beaks, and afterwards tearing them to pieces. Wounded or disabled birds they remorselessly devour. In the breeding-places they plunder the nests, breaking the eggs and swallowing the young. "A general shriek," says Nordmann, "rises from a thousand throats as soon as one of these marauders is seen winging his way towards the rock, and yet none of the brooding birds will venture to offer anything like a serious resistance to the invader. He seizes hold of the young birds, wrenching them from the very beaks of their parents, who only follow the robber to a little distance from the nest, without any effectual result. So soon as the thief finds himself no longer pursued, he flies down to the sea, kills and devours his prey, and then flies off with it to his own nest, where he disgorges it for the benefit of his young family. When making these raids, the Skua has never been observed to use any other weapon than his beak, although it would seem probable, from the sharpness of his powerful, strongly-hooked claws, that they likewise may be resorted to as formidable instruments of attack. After a plentiful meal, the Skua betakes himself to some rock, where he sits for a time with puffed-out feathers, apparently enjoying a luxurious nap, and in that position he remains till the calls of hunger again prompt him to active exertion." About the beginning of May, the Skuas may be seen congregating in pairs in the vicinity of their breeding-places, where, upon some rocky platform or moss-grown overhanging ledge, they construct their nests. These are generally mere cavities, hollowed out by the pressure of their bodies, and here, during the first days of June, they lay two eggs of a dirty olive-green colour, spotted with brown. One of their breeding-places visited by Graba was occupied by about fifty couples. According to Mr. Dunn, this species has three breeding-places in the Shetland Isles--Foula, Rona's Hill, and the Isle of Unst. In the latter place it is by no means numerous, and is strictly preserved by the landlords on whose property it may have settled, from a supposition that it will defend their flocks from the attack of the Eagle. That it will attack the Eagle if he approaches its nest is a fact that I have witnessed. I once saw a pair beat off a large Eagle from their breeding-place on Rona's Hill.