Capercaillie (Tetrao urogallus)

SizeMale weight: over 4 kg
Female weight: up to 2 kg
Male body length: 74 – 90 cm
Wingspan: 87 – 125 cm

The capercaillie is classified as Least Concern (LC) on the IUCN Red List (1). Listed on Annex 1 of the Birds Directive and Appendix II of the Bern Convention. It is also listed on Schedules 2, 3 and 9 of the Wildlife and Countryside Act 1981.

The male capercaillie (Tetrao urogallus) is a game bird, and the largest member of the grouse family resembling, to some people, a turkey. Males are slate-grey over most of their bodies, and have reddish-brown upper wings with a prominent white shoulder (carpal) flash. The head, neck and breast have a blue sheen, with the eye surrounded by a ring of bright red skin. Male birds have a ‘beard’, especially noticeable when they are displaying, and a long tail, held upright and fanned out during their displays. Females are much smaller birds and lack the flamboyant plumage of the male. They resemble females of the other members of the grouse family in the UK, but are larger. The plumage is brown with striations over much of the body. There is a rufous patch on the breast and the tail is fan-shaped, although not as broad as that of the male. The males have a spectacular spring display during which they produce a series of odd calls, including sounds like the popping of corks.

The capercaillie became extinct in Britain in the 18th century, as a result of wide-scale forest clearance and hunting. Birds from Sweden were re-introduced into Scotland in the 19th century. Its current UK range is centred on the Cairngorm region of upland Scotland, but extends westward to the woodland around Loch Lomond and northwards to Spey side.

The Scottish birds represent a very small percentage of the world population, which extends throughout the forests of mountainous and boreal regions of Scandinavia, central Europe, northern Asia and Siberia. This range, too, is also declining as a result of forest clearance.

The Scottish population is restricted largely to pine forests, in particular the old Caledonian Forest habitat, although it will tolerate man-made plantations as long as they provide suitable feeding and ‘lekking’ sites. It is important that the woodland contains trees of differing age ranges as well as boggy areas providing a good source of insects for chick feeding. Equally vital is the availability of open areas where the male birds can perform their courtship ‘leks’.

In April, the male capercaillies move to an open part of their woodland territory and perform their ‘lek’. Lek is an Old Norse word meaning ‘to dance’, and relates to the birds’ bizarre courtship display. The males strut about with their tails fanned out, and wings held down, while producing an extraordinary sequence of noises including some that sound like strangled gurgles and asthmatic wheezes. Interspersed with these are popping noises like corks being drawn from champagne bottles. Some experts believe that some of these sounds, below the range of human ears, carry for many miles and declare to any female capercaillie that the male making the noise is in his prime. They may also indicate that he has a fine territory, well provided with nesting sites and a good food source for the chicks. As the females arrive at the lekking site, the males become even more excited. Sometimes, several males will gather at a lekking site and spectacular fights can break out, during which birds can be seriously injured and even killed.

Once the female has been mated, the males play no further part in rearing the young. Between 5 and 12 eggs is the usual clutch, but as many as 18 have been recorded. They are laid in a nest on the ground, lined with pieces of nearby vegetation. Incubation takes from 26 to 29 days and the young chicks, like those of all game birds, are highly mobile, leaving the nest with the female the day after they hatch. Their wing feathers appear in two weeks and the young birds are then able to fly, albeit rather weakly. They stay as a family throughout the rest of the summer months, joining larger groups of birds in the autumn.

Capercaillie feed on blaeberries (also known as bilberries), shoots and seeds. In common with many birds, the chicks are fed initially on insects, graduating to the more vegetable-based adult diet later.

The principle threats to the capercaillie are thought to be loss of habitat through overgrazing by sheep and deer, predation, and collisions with deer fences. Over-shooting may also be a contributing factor, and a succession of poor summers has affected the number of chicks surviving infancy.

The capercaillie is listed in the UK Biodiversity Action Plan, and figures released in a joint survey by the RSPB and Scottish Natural Heritage in 2003 suggest it may number just 1,000 individual birds. This is a 50 percent reduction in numbers in the space of just five years, and a similar decline is evident throughout the bird’s European range.

Deer fencing is a relatively recent threat to capercaillies. Fences tall enough to restrict the movement of deer present a serious danger to a low-flying, heavy bird like the capercaillie. It is known that nearly a third of the total population of birds were lost to this hazard, and new management techniques are now being trialed to reduce the incidence of fence collisions.

In October 2002, a number of conservation organisations made a joint bid for funds from European LIFE Nature. This bid resulted in a grant of £4.5m to be spent on ‘Urgent Conservation Management for Capercaillie in Scotland’. Hopefully, as a result of a variety of actions under the LIFE project, including improved habitat management, predator control and the removal or marking of fences, this magnificent bird will remain a characteristic feature of the Highlands wildlife, and continue to perform its extraordinary dance routine.

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  1. IUCN Red List (April, 2011)