Common crane

Latin Grus grus (L.)
Estonian Sookurg

Also known as: Eurasian crane

Status in Estonia

Breeding and migratory bird.

Description

This bird is a big crane with extremely long legs and a long, thin neck. The plumage is usually light bluish-grey, but most breeding birds develop a rust-brown back from exposure to bog water during the incubation period. The head and upper neck are black and white, while the skin on the nape and crown is red. The elongated tertials are extremely puffy and dishevelled, the tail feathers are grey-black. The sexes appear the same; however, when a couple is together, the male bird appears larger. The wings are long and rectangular with ‘fingered’ tips. The juvenile’s head and upper neck are a pale red-brown, lacking the black-white-red head pattern of the adult bird, and the fluffy tertials are sparser.

Size

Body length 96–119 cm, wingspan 180–222 cm. Body mass 4.1–6 kg.

Similar species

Grey heron, white stork.

Distribution

Scandinavia is the northernmost point of distribution in Europe, Central Siberia is the easternmost point in Asia and Central Asia is the southernmost. Common cranes that breed in Europe winter primarily in Spain and the Mediterranean countries, with a small population wintering in Ethiopia. It is a very common breeding bird in Estonia. The common cranes that breed in our country winter primarily in Spain and the Mediterranean countries, with a few in Northeastern Africa.

Population

Estonia has 7000–8000 breeding pairs.

Occurrence in Estonia

In some instances, they can arrive as early as the end of February in the spring, although most arrive between March and April. The migration begins in the second half of August, but most depart around October.

Diet

Its diet is primarily plant-based, including berries, grass blades and seeds. It also eat small animals such as frogs, snakes, insects and rodents.

Habitat

The species exclusively avoids large forested areas and agricultural landscapes where there are no adequate wetlands for nesting. Fens have the highest number of nests found, followed by raised bogs, wet forests and inland small lake environments.

Nesting

Courtship rituals take place prior to nesting. Courtship rituals include bending the neck backwards and performing a deafening duet. A typical nest site is wet but usually lacks deeper open water. The nest is often found in a small fen or a vegetated quarry as well as in a swamp puddle in the forest with a diameter of only twenty metres. It is not a skilled nest builder. It frequently covers the surface opening with a layer of dry grass blades or gathers a small mound of twigs or reeds for a base. At the end of April, the female bird lays two 150–200 g reddish-brown, sometimes greenish-brown, rust-coloured eggs, which are incubated by both parents until the chicks hatch. The chicks hatch at the end of May or June, and they can fly by the end of July. The fledglings leave the nest during the day to forage for food, returning in the evening to spend the night.

Conservation status and protection

It belongs to the protected bird species of category III. The main threats across the distribution area include habitat degradation or decline in quality, disturbance during breeding, droughts and illegal hunting. The most significant risk factors in Estonia are increased disturbance during nesting and predation of chicks by small predators, birds of prey and wild boars due to their huge population. As the climate warms up, the amount and quality of wetlands ideal for nesting may diminish.

Distribution and population in Lääne County

The common crane is a common breeding and migratory bird in Lääne County. The loud mating call of common cranes can be heard already in early March. They build their nests in wet areas to help protect it from predators. However, during the breeding season, you can see common cranes feeding in the fields.
In September, birds that breed in Finland arrive in Lääne County alongside local cranes. Large migrating flocks of common cranes can be spotted in the fields at that time. However, viewing common cranes’ nocturnal flight on autumn evenings provides a unique spectacle. Thousands of common cranes make their way to Matsalu and Haapsalu bays before dusk to spend the night. On some evenings, Matsalu Bay can have around 20,000 birds. To watch them, visit Rannajõe or Haeska observation tower.