The Eurasian Black Grouse (Lyrurus tetrix) is a roughly chicken-sized bird native to the Eurasian continent. Like all other 19 members of the Grouse tribe (Tetraonini), L. tetrix can be found only in the northern hemisphere. They are well adapted to colder climates and share many of the characteristics common to grouses, like a compact body, short wings and legs, dense plumage as well as feet covered in feathers during winter, to name a few.
L. tetrix has a broad distribution range, spanning from Scotland in the west all the way to eastern Russia. The northernmost population can be found in Norway at approx. 70°N while the Alps and Tian Shan mountains mark the southernmost points of its distribution range at approx. 45°N.
Despite this extensive geographical distribution, these birds have become critically endangered in Germany due to extensive habitat loss. Nowadays, they can only be found in a handful of areas. Conservation efforts are therefore put in place to ensure that this species persists and can be admired by future generations. At this point I feel obliged to point out that it is punishble by law in Germany to “significantly disturb these animals during mating and raising season”. So please make sure to stay out of denoted wildlife protection areas year round, and especially during early spring!
Appearance
Like many other birds, L. tetrix displays what is known as sexual dimorphism – i.e. males and females look different. With approx. 45cm in size and a max. weight of 1100g, females are significantly smaller than their male coutnerparts at about 60cm and 1750g. Similarly, males have larger wing spans of up to 80cm, while females usually come in at about 60-65cm.
Besides the differences in size and weight, the two sexes are also easily distinguishable by their coloration and patterning. As with many animal species, the females of L. tetrix have a much less “showy” appearance than the males. The females‘ primary coloration of brownish, earth-like tones in combination with the dotted/striped patterning camouflages them very well in their natural habitat. A trait that is particularly important during nesting season to avoid predation.
Males, on the other hand, are much less camouflaged and are easily identified by their prominent plumage dominated by black tones shimmering in shades of blue and green when in direct sunlight. White feathers of the wingline and undertail coverts contrast the otherwise black body. A male’s tail feathers curl outward and resemble the shape of a Greek lyre when on display – hence the genus name Lyrurus. Even outside of mating season, the patches of red skin above the eyes are very noticeable. These so called Roses swell during early spring and become even more noticeable.
Male
- Plumage: primarily black shimmering blue/greenish in direct sunlight
- Size: up to 60cm
- Wingspan: up to 80cm
- Weight: up to 1.8kg
- Bare, red skin above eyes (Roses) that swell during mating season
- Compete with other males in leks during mating season
- Tail feathers resemble a Greek lyre, hence the genus name Lyrurus
Female
- Plumage: brownish earth-tones, dotted, well camouflaged
- Size: up to 45cm
- Wingspan: up to 65cm
- Weight: up to 1.2kg
- Responsible for raising the chicks
Habitat
L. tetrix are found from alpine regions to moorlands where they inhabit open landscapes interspersed with shrubs and light forest cover. Because these birds are somewhat sedentary – i.e. they do not migrate over long distances, they have various requirements to their habitat:
- Richly structured habitat with dwarf-shrubs separated by narrow corridors used for moving around without being spotted
- light forest cover providing means of escape from terrestrial predators like red foxes, lynx, etc.
- various food sources available throughout the year (see Diet)
- rich insect populations during spring for upbringing of chicks
Of particular importance are stretches of open land with very little to no shrubs during the mating season. Here, males compete against each other in so called leks for the favor of the hens. These leks remain virtually the same over the years, so once you have found one there is a very high chance of witnessing males competing there in the future as well.
Diet
Like most Tetraonini, adult L. tetrix are herbivorous throughout most of the year. The only exception is during molt (the annual replacement of plumage from June – October) when an increasing percentage of their diet consists of insects and other invertebrates.
Because they live in the northern hemisphere, their diet changes over the course of a year according to what is available during the respective season. During spring, shoots and buds of various plants form the majority of their diet. In summer, they feed on flowers and other herbaceous plants which are replaced by berries (blueberries, cowberries, etc.) during fall. Winter marks the most difficult time of the year for these birds. While food is scarce, they rely on buds of trees sticking out from the snow and are sometimes observed eating needles of coniferous plants if there is no other option.
Chicks on the other side have a much higher demand for protein which is why they feed exclusively on insects and other invertebrates during their first few months. This allows them to grow quickly in order to withstand the harsh winters.
Behavior
L. tetrix are rather elusive, solitary animals. They are mostly active during the morning and evening hours just around sunrise and sunset and spend much of the day hiding in underbrush or carefully and slowly moving around to avoid detection. This goes hand in hand with the fact that these birds rarely ever give off sounds, with mating season being the exception.
Spotting these animals out in the field can thus be quite a challenge and you should consider yourself lucky if you do see one. Knowing where to look for them and patience are key when planning on finding them.
Mating season
Mating season marks a particularly interesting time to observe (and photograph…) these otherwise elusive animals. From late March to early June, males visit leks displaying their courtship ritual hoping to attract nearby females that are often watching from a safe distance up in a tree/bush. The strongest males usually occupy the central area of a lek, while younger males attempt to attract females in smaller leks around the central one. Contrary to other birds/animals, males do not physically fight over females but rather assert dominance via threatening postures.
If a female feels attracted to one of the males, she enters the lek to mate. Shortly after, the hen flies off to a bush suitable to build a well hidden nest on the ground to lay 7-10 eggs. The chicks hatch about 3-4 weeks later and start feeding on insects and other small invertebrates right away. They are constantly accompanied and guarded by the female and are able to fly after only 15-20 days. In late September, the female separates from the chicks.