Cassell's book of birds; vol. 4

by Alfred Edmund Brehm

The SKUAS (Lestres), although resembling the Gulls in shape and plumage, differ from them in so many particulars that they must be regarded as forming a separate family. The principal points of difference between these birds and the true Sea Gulls are found in the structure of the beak and feet, as also in the peculiarity of their colours, and in their mode of life.

In the Skuas the body is strongly built, the neck short, the head small, the beak moderately short but strong, thick, and towards the apex compressed. The upper mandible is vaulted above, strongly hooked, and provided at its base with a cere. The tarsus is moderately high, the toes short, but with a very complete web, and furnished with crooked, sharp-pointed, and sharp-edged claws. The wings are long, narrow, and pointed, the first quill being the longest. The tail consists of twelve feathers, of moderate length, and has the central tail-feathers prolonged. The plumage is rich and thick, upon the under surface fur-like; its prevailing colour is a dusky brown.

The Skuas, or Parasite Gulls, are most abundant in the Arctic Regions. They live principally in the open sea, but at their breeding-time seek the neighbourhood of coasts and islands. Occasionally they wing their way into more southern latitudes, and sometimes are to be seen far inland. In strength of wing they are superior to the Gulls, and they swim well, but prefer flying to swimming. In a certain sense, they might be said to hold a middle position between Sea Gulls and birds of prey. They attack all animals that they are able to subdue, and persecute their weaker brethren until they oblige them to yield up whatsoever prey they may have caught. Indeed, it was recently generally believed that they were unable to catch prey for themselves, but were obliged to live the life of freebooters, and depend upon thieving for their support; modern observations have, however, shown that this is not altogether correct. It is, however, quite true that their power of diving is not such as to enable them to catch fishes at any great depth; they can only procure such as may be swimming close to the[Pg 199] surface. They are, however, by no means confined to a fish diet; they devour birds and their eggs, kill small quadrupeds, and prey upon shell-fish of every kind. They will even attack young lambs, hack out their eyes and brains, and, in short, prey upon everything that offers itself, whether living or dead. Generally, however, they live by the labour of other diving birds. They watch the Gulls, Terns, Guillemots, and other predatory species, and whenever they perceive that they have caught a fish, hasten after them with all speed, and so torment and worry them as to compel them to disgorge their already swallowed prey, and let it drop from their mouths. No sooner do their pursuers see it fall than, swooping after it with the speed of a Falcon, they catch it before it reaches the water, and appropriate it to their own use. Such barefaced robbery as this naturally causes the Skuas to be detested by all seafaring birds; nevertheless, they seem to care very little for the general hatred, and recklessly pursue their system of plunder whenever opportunity offers. No sea-bird will brood in their vicinity, or remain upon any inland lake of which they have possession. Every individual who has once made their acquaintance endeavours, as the sailors say, to give them a wide berth. The more valorous species often attack them furiously; the timid flee at their approach, or if they are in a position which enables them to do so, dive out of their sight. When their breeding-time arrives, the Skuas assemble in small parties, and build their nests in company with each other. The places selected for this purpose are generally large islands, some species preferring the level of the shore, others the summits of the highest rocks. In these localities they scratch or construct for themselves a round excavation in the sand, and, if practicable, concealed among plants, and in the ample nest lay two or three eggs, upon which the male and female sit alternately. The young are fed at first with food partially digested in the stomachs of their parents, subsequently upon coarser diet. They remain in the nest for several days, and when they leave it run about on the beach like young birds, hiding themselves, in case of danger, between the stones, or among the inequalities of the ground. After they have become capable of flight, they continue for some time in the neighbourhood of the coast, profit by their parents' instructions, and in their company they at last fly away to the open sea. In the second summer of their lives they begin to breed. The eggs of the Skuas are eaten by the inhabitants of northern countries, but the birds themselves are considered worthless; nevertheless, they are killed in great numbers. The chase after them is easy enough, inasmuch as they will greedily swallow any kind of bait, and fear man no more than they do the birds that they plunder.

THE COMMON SKUA.

The COMMON SKUA (Lestris catarractes), the most conspicuous member of the above family, is twenty-two inches long, fifty-two inches broad; the length of its wing sixteen inches and a half, of the tail, six inches and a half. The colour of its plumage is greyish brown, the somewhat lighter under surface is striped longitudinally with pale or red grey; a space at the base of the dark-coloured wing is white; the eye is red-brown; the beak leaden grey at the root, and black at the apex; the foot blackish grey. The young birds resemble the adults.

Although the proper climate of the Skua is between 60° and 70° north latitude, it has also been met with in the temperate zone of the southern hemisphere. In Europe its head-quarters are in the vicinity of the Faroe and Shetland Islands; also on the coasts of Iceland, and the Orkneys and Hebrides, ranging from thence, in the winter season, to the northern shores of France, England, and Germany. The greater number of them, however, remain constantly in the north, seeking for their food wherever the sea may happen to be free from ice.

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THE COMMON SKUA (Lestris catarractes).

The Skua is recognisable from the larger Gulls by the varied character, facility, and rapidity of its movements. It runs quickly when upon dry land, swims beautifully, floating with its breast deeply immersed, and rises easily into the air, whether from the sea or from level ground. The flight of this bird resembles that of the larger Sea Gulls, but is not so equable. Sometimes the celerity of its movements will bear comparison with those of the Hawks and Eagles. Sometimes it skims over the surface of the sea without the slightest perceptible motion of its wings, or rushes from a great height obliquely downwards towards the surface of the sea, tearing through the air with surprising rapidity. In daring, thieving, and unsociableness it not only far exceeds the Gulls, but surpasses every other sea-bird. Of all the tyrants of the sea it is the most universally dreaded; it has no participation or friendship with any other species; and although only the strongest of its enemies ever venture to attack so redoubtable a foe, it is held in universal abhorrence. The opinion entertained by other birds as to its cunning and ferocity is best exemplified by the fact that even such as are far larger and stronger than their oppressors submit to be robbed and bullied in the manner we have described, without making the slightest resistance. The appetite of the Skuas is exactly proportioned to their restlessness and activity. So long as they are on the wing they are constantly employed in satisfying the cravings of their ravenous maw. Should no other bird appear in sight upon which to exercise their avocation as highwaymen, they are under the necessity of fishing for themselves, and if not successful in their endeavours to obtain a meal, have recourse to the shore, upon which they diligently search for anything in the shape of food that may have been left by the receding tide. Should this resource likewise fail them, they fly off into the fields and inland marshes, where they pick up worms, insects, and small mollusca; or should they meet with a sea-bird similarly occupied, they at once give chase, exhibiting[Pg 201] as much strength and skilfulness in the use of their wings as they do courage and audacity in planning their attack, never leaving their victim until they have made him disgorge the contents of his stomach, and appropriated it to their own use. 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."