Studies of an aggressive Capercaillie Photographs by C. E. Palmar (Plates 1-5)

THE FIRST FOUR PLATES in this issue are all of a remarkably aggressive cock Capercaillie (Tetrao urogallus) which lived in a small wood near the top of Glen Lethnot, near Brechin, Angus, for at least four years up to June 1961. Each spring, from late February to the end of June, it would persistently attack all human beings, most other large animals and even any vehicles which entered its territory during the hours of daylight. The incident has been described in some detail by Jenkins (1962) and the next paragraph is a summary of the main points. This Capercaillie was the only male in the area. It was most aggressive inside the wood, which was some 35-40 acres in extent, but it also readily came out on to the road and a neighbouring grass field. Fortunately the place was very quiet and traffic infrequent, or the bird would probably not have survived as long as it did, for it many times attacked cars, land-rovers and post office and other vans, occasionally even landing on them. C. Crystal, the head keeper, could often summon it by calling or by sounding the horn of his land-rover. When attacking human beings, it would deliver quite hard blows with its wings and peck vigorously with its beak, sometimes even holding on; its nip could be felt through rubber boots. It was so aggressive in 1961 (more so than in i960) that it was necessary to hold it oft "with a forked stick in order to photograph it (plate 4). That year it also jumped on top of Mrs. Palmar when she tripped and fell, and it drove C. K. Mylne backwards through the wood, battering his camera tripod. It attacked sheep in the wood and a horse in the meadow outside, frightening the latter to such an extent that the unfortunate animal confined its movements to the far end of the field. On the other hand, it never attacked a dog and it bit off more than it could chew when it was trapped against a tree by a ewe with a lamb; it lost some of its tail-feathers in this encounter and the gap can be seen in plates 1 and 3. There was no obvious resurgence of aggressiveness in autumn when, for example, Blackcocks (Lyrurus tetrix) often return to their leks. It finally disappeared in June 1961 and was presumed to be dead. Jenkins also quoted three other cases of similar behaviour. Two of these had previously been published, the first concerning a bird in Rothiemurchus Forest, Inverness-shire, which attacked children

19 BRITISH BIRDS going to school and. ladies with silk stockings (Gordon 1951), and the second an aggressive individual in Glen Lyon, Perthshire (Rich­ mond 1958). The third case, reported to him by A. Walker of the Grouse and Moorland Ecology Unit, involved attacks on people near Corrour Station, Inverness-shire, in the springs of 1940-43. In a lifetime's experience of keepering in Scotland, this was the only directly comparable instance that Mr. Walker had come across, though he was able to add that in Glen Tanar in August 1926 he was attacked by a cock Capercaillie which he had shot and wounded, and that a farmer near Banchory, Kincardineshire, in June 1961 was set upon by a hen Capercaillie when he approached her brood. A fifth case of regular attack on human beings was described by Mylne (1962). This bird lived in an extensive larch wood near Dunkeld, Perthshire, and, like the Glen Lethnot one, was believed to be the only male in the area. Its territory was smaller than that of the Glen Lethnot bird, but it would still attack fifty yards or so from the mound which appeared to be its chief display ground. In 1961 its mate had a nest about the same distance away, but the aggressiveness was in no way affected when the eggs came to grief. This cock Capercaillie had been quite notorious in the district for at least five years, but it also could not be found in 1962. It was apparently easily scared by dogs, but it would attack any human being or vehicle which entered its territory. It was so aggressive, in fact, that it always had to be held off with a forked stick, against which it would make persistent rushes; once it kept up the onslaught for over an hour without any sign of flagging. A 16 mm. film was obtained of this bird attacking first a car and its occupants, then its own reflection in a mirror and finally a stuffed cock Capercaillie. It attacked mostly with its wings, using one at a time to deliver a hard blow with the carpal joint. It also used its bill, but to a lesser extent. When it attacked the mirror, it hit the glass so hard with its wing that its carpal joint was bleeding after three or four blows and the mirror had to be withdrawn to prevent further injury. Mylne concluded his article by describing the reactions of this bird to stuffed Capercaillies of both sexes. The small number of records of this kind suggests that such highly aggressive Capercaillies are not very frequent, or at least that they do not normally overcome their fear of human beings. In most of the cases quoted, the birds concerned lived near roads and saw people fairly frequently, as a result of which they may have grown bolder. Mylne, reasoning from the fact that the Glen Lethnot and Dunkeld birds were believed to be the only males in their respective areas, suggested that isolation from rivals might be the explanation: with no rivals to attack or display against, the aggressive drive of such birds

20 AGGRESSIVE CAPERCAILLIES might be turned towards any other large moving object. Jenkins pointed out that Scandinavian biologists with whom he had discussed this behaviour had never recorded a Capercaillie attacking a human being. In Norway and Sweden, however, Capercaillies are important game-birds and bold ones would be likely to get shot; in those countries, too, there are more natural predators to destroy the in­ cautious individual. Although only one of C. E. Palmar's excellent photographs of the Glen Lethnot bird shows it actually attacking (plate 4), the others serve to illustrate some of the points lately brought out in this journal by Lumsden (1961). In both song and threat postures (including the first stage of the bowing display or high intensity threat) the neck is held upright and the long feathers beneath the bill are erected like a beard, while the wings are drooped to expose the white shoulder patches and the tail is spread like a fan. The essential difference between the song display and the threat and bowing displays is in the sounds made and the resulting positions of the feathers on the neck and upper breast. In song the neck is more vertical, the bill is pointed skywards and the neck and breast feathers are flattened. In threat the bill is in a more normal position and the neck and upper breast feathers are usually erected, thus substituting a dense black area for the green sheen which otherwise shows on this part of the plumage. The different appearance of the neck when the feathers are erected from when they are not can be seen by a comparison of plates 1 and 3, and more graphically in plate z. It should be added, however, that the neck and breast feathers are not always raised in threat and, judging from the position of bill, neck and tail, plate 3 (and plate 2a which is an enlargement of it) actually represents a lower intensity of threat rather than the true song posture. The differences in the postures were perhaps best shown by some Scandinavian photographs of Capercaillie by Kurt Ellstrom, Enar Sjoberg and Jonas Svensk, which were reproduced in British Birds in 1958 (51: plates 29-32). There the high intensity threat (with the feathers of the upper back of the neck only slightly erected and their tips flat to present a smooth appear­ ance, but the feathers of the rest of the neck and upper breast standing out raggedly) was well illustrated on plates 30 and 31b, while the true song posture (with raised bill and flat neck) was shown on plate 29. As pointed out by Lumsden, the caption to plate 30 wrongly suggested that it was the song posture. For a full discussion of Capercaillie displays, and some excellent drawings, the reader is referred to Lumsden's paper. The last Capercaillie picture in this issue (plate 5) has no connection with the others, but we are glad to take this opportunity of using it as there can be few photographs of one of these magnificent birds in

21 BRITISH BIRDS flight. Mr. Palmar's shot of a male over Loch Lomond well shows the distinctive silhouette of long, thick neck and broad wings. IJ.F.-L.

REFERENCES GORDON, S. (1951): The Highlands of Scotland. London. JENKINS, D. (1962): 'Aggressive Capercailyes'. Scottish Birds, 2: 81-82. LUMSDEN, H. G. (1961): "The display of the Capercaillie*. Brit. Birds, 54: 257-272. MYLNE, C. K. (1962): 'Aggressive Capercaillies'. Scottish Birds, 2: 82-84. RICHMOND, W. K. (1958): In Annual Report of Scottish Field Studies Association.

22 PLATE I. Male Capercaillie (Tetrao urogallus), Angus, spring 1961. This is a threat posture, with the bill partly raised, the 'bristles' under the chin standing right out, and the feathers of neck and upper breast ruffled. Note also the white carpal patch, drooping wings and fanned tail (pages 19-22) {photo: C. E. Palmar)

PLATES 2 and 3. Further views of the same Capercaillie (Tetrao urogallus). The neck-feathers are flattened in the picture above (cf. plate 1), and this difference in intensity of threat is shown graphically in the close-ups opposite (page 21); the bill is whitish and the bare skin round the eye bright red {photos: C. E. Pa/mar) PLATE 4 (below). Keeper Charles Crystal keeps the male CapercailHe (Tetrao urogallus) at bay with a forked stick while the Palmar family look on from a few feet away. This bird would deliver quite hard blows with its wings, and peck and nip with its beak. It would attack any people, vehicles, sheep or horses (but never dogs) which entered its territory between February and June. It lost some of its tail-feathers in an encounter with a ewe (page 19) PLATE 5 {above). A Capercaillie (Jetrao urogallus) flying over Loch Lomond. Weighing up to 14 lb., these birds are noisy and awkward as they break cover, but travel easily and silently once under way. Like other game-birds, they fly with a series of quick wing-beats interspersed by periods of gliding. They usually fly for short distances only, but at times well up in the air for several miles. Note the long, thick neck and broad wings {photos: C. E. Palmar)