Hen harrier

Latin Circus cyaneus L.

Estonian Välja-loorkull

Also known as: ghost of the moor

Status in Estonia

Breeding, migratory and wintering bird.

Description

The hen harrier is a falcon with a slender body and is approximately the size of a common raven. Male and female birds differ significantly in appearance. The male bird is slightly smaller than the female and its colour is predominantly light grey. The underside is lighter than the rest of the body, while the top coverts of the wings are darker. A circle of dark feathers surrounds the eyes and in direct view, it meets at the dark beak. The female bird is larger than the male and both its back and wings are brown. The female bird’s underside is light-coloured with contrasting dark stripes. The head is dark, the tail has brown streaks and during flight she keeps it fanned out. The preen gland of the hen harrier is pure white. The bird’s legs are bare up until the end of the tibiotarsus and yellow with black claws. Juveniles look similar to females, but their backs are darker brown.

Size

The hen harrier is about the size of a common raven, with a total length of up to 55 cm and wingspan of 33–36 cm for males and 37–40 cm for females. Male birds weigh 290–390 g, whereas female birds weigh 390–600 g.

Similar species

Montagu’s harrier, pallid harrier, Western marsh harrier.

Distribution

The hen harrier is common in the Northern Hemisphere’s forests, steppes and Mediterranean zones. It is a common bird in Estonia with a local distribution, specifically in bigger bushy bogs.

Population

Estonia has 10–30 breeding pairs. About 5–50 individuals winter here. In winter, the species is more common in Western Estonia and on the islands.

 Occurrence in Estonia

The hen harrier arrives in Estonia at the end of March or in early April and departs at the end of August or in early September.

 Diet

The hen harrier’s prey includes small mammals, primarily ground-dwelling birds as well as their chicks and eggs. It also attacks gulls and shorebirds.

Habitat

It lives in bushes, bogs with shrubs and low forest areas, river flood-meadows and other wetlands. It is most common around the Emajõe River systems, the Narva River flood-meadows and Western Estonia’s bushy bogs.

Nesting

The hen harrier’s nest, which is normally on the ground, can be found in a variety of biotopes but is usually well hidden by shrubs. In Estonia, the most common nest sites in the previous decade have been 5–20-year-old bushy clearings, but nests have also been discovered on the borders of bogs with sparse tree growth and boggy grasslands. The outside of the nest is made of twigs or dry grass and the inside is lined with softer dried grass. It lays 3–6 whitish eggs in May. Chicks hatch in mid-June and remain in and around the nest until mid-July, when they start to fly.

Conservation status and protection

It belongs to the protected species of category III. The most significant threats include the destruction of open landscapes ideal for hunting as a result of barren vegetation, large-scale drainage or intense agricultural activities. As a ground breeder, it has many enemies, including mustelids and birds of prey. It is also under threat from pesticides through its dietary sources.

Distribution and population in Lääne County

The hen harrier is an uncommon migratory bird in Lääne County and only some individuals stay here for the winter. Migrating hen harriers can be seen searching for prey in fields and flood-meadows, but they occasionally glide over reed beds.

The observation tower at Rannajõe provides a good view of hen harriers. In September and October, you may see their small-numbered migration in Cape Puise.