A book which treats of Adélie penguins scarcely can be complete without reference to the beautiful McCormick's skua gull (Megalestris maccormicki), as probably no Adélie rookery exists without its attendant band of skuas, who build their own nests very close to and occasionally among those of the penguins on whom they prey, almost entirely supporting themselves and their young upon the eggs and young offspring of their hosts.
Mention has been made of these birds from time to time through the previous pages, and some idea of their habits already will have been formed. In point of fearlessness they fall somewhat short of the Adélie, but exhibit, perhaps, rather more caution in their dealings with man than the gulls who visit St. James's Park in London and are fed by the children there, frequently from the hand, though probably in a very few days they might become extremely tame were their short experience of mankind made less bitter. The majority of explorers, like most men, though kindly by nature, are entirely thoughtless in their dealings with wild animals, and the skuas approach them only to be killed or severely injured by the ice-axes or rocks that are thrown at them in wanton sport as they light on the ground or hover near the visitors, whom they quickly discover to be their bitter and relentless foes.
Arriving at the rookeries somewhat later than the Adélies, they do not lay their eggs until the beginning of December. Practically no nest is made, a mere hollow being worked in the ground, in which the bird sits. Frequently several hollows are made before the hen finally settles where she will lay. The two eggs, which are brownish olive thickly and darkly mottled with brown, are incubated for four weeks, after which the chicks are hatched.
From the moment of their first appearance from the egg these chicks exhibit the most extraordinary precocity. Covered with pale slaty-grey down, they look anything but the pugnacious little animals they turn out to be. Their one idea, besides feeding, seems to be to fight one another, and they may be seen to roll about the nest, locked together, fighting with beak and claw. They are fed from the ground, and may be seen picking about among the stones like the little domestic chickens, which they very much resemble. After a time invariably one of the chicks disappears, and as dead youngsters are not to be found, they are probably eaten by neighbours who have caught them wandering; in fact, Mr. Ferrar, of Captain Scott's first expedition, actually saw a Skua pick up a wandering chick of its own species and fly off with it, followed by a screaming flock of its neighbours, who sought to rob it of its prey.
In order to find out how many eggs a Skua would lay, I marked some nests, and took the eggs as they were laid. In each case a second egg was laid, but when this was taken no more appeared. In two nests I removed the first egg as soon as it was laid, but left the second, which was then sat upon by the parent, who was content with it, or unable to lay a third.
When any of us approached their nests the old birds would fly round in wide circles, making wild “stoops” at our heads each time they passed over us, in the evident attempt to frighten us away. Occasionally they would actually knock our heads with a wing, and nothing seeming to scare them off, they would swoop past us time after time in a most disconcerting manner. In order to keep them at a distance without having to keep a constant look-out, when I was in the neighbourhood of their nest, I used to walk about holding a ski-stick or the handle of my ice-axe straight above me, and they would swoop at the top of this instead of my head, which was infinitely preferable. One day when a high wind was blowing on top of Cape Adare, I had my ice-axe knocked clean out of my hand by one of the Skuas flying straight into the handle, the heavy blow seeming to affect the bird but slightly.
There was a “skuary” on the screes, close to a thickly populated part of the rookery, but the majority of these birds made their nests right at the top of Cape Adare, from which point of vantage they surveyed the entire rookery, and a very sharp look-out they kept too, for no sooner did we start to flense a seal than a flock of them descended to gobble at the lumps of blubber as we threw them on the ground. In this occupation they exhibited the greatest jealousy, and when there was a hundred times as much blubber on the ground as all the skuas possibly could have eaten, they continually tried to drive each other away. When fighting they rarely stayed on the ground, but leapt at one another into the air, and one of the illustrations shows two Skuas in the act of doing this. Their great spread of wing is well shown in this photograph. ([Fig. 71.])
When penguins' eggs were plentiful in the rookery the Skuas flew very low over the ground, and as they passed over each colony of nests the sitting birds would crouch low upon them, a very necessary precaution, as I have described already in these pages the unerring way in which the Skuas picked up the penguins' eggs when they were left uncovered. Broken and empty shells strewed the ground in the vicinity of the Skuas' nests, and it is probable that in a large rookery, such as that at Cape Adare, thousands of eggs are destroyed by them annually.
The instinct of the thief is most strongly marked in the Skua tribe, and I am afraid that the mere love of thieving alone actuates them on many occasions. For instance, when I was skinning a seal one day near Cape Evans I left a pair of field-glasses lying on a coat close by, and on looking round saw a Skua in the act of making off with them, holding them by the strap in his beak. A sudden yell caused the offender to drop the glasses, fortunately when they were but a yard from the ground. Again, when the crew of an Antarctic ship were engaged in blasting the sea-ice which imprisoned it, a Skua flew off with one of the detonators which had been left on the ice. I think the detonator contained dynamite, but at any rate I am told that there was a stampede on the part of the men to get away from under the bird as it flew overhead!
When, with two companions, I visited a skuary at the back of the penguin rookery at Cape Royds, the Skuas circled over us in a way I have described above, but instead of swooping at our heads, some of them repeatedly dropped their guano on to us as they passed over, timing the process with such surprising accuracy that I was hit once, and Commander Campbell no less than three times. The following year when at Cape Adare, I expected the same treatment from the Skuas there, but curiously enough, these never did it. That one skuary should have adopted such tactics and another not, is a very curious thing, but it may possibly be that the Cape Royds Skuas discovered the trick during the stay of Sir Ernest Shackleton's expedition, who had spent a year there quite recently, and of the Discovery expedition which spent two years at Hut Point, but a few miles distant, whereas the only men who ever inhabited Cape Adare wintered there some fifteen years before. But this is mere speculation.