The Eurasian bittern or great bittern (Botaurus stellaris) is a wading bird in the bittern subfamily (Botaurinae) of the heron family Ardeidae. There are two subspecies, the northern race (B. s. stellaris) breeding in parts of Europe and across the Palearctic, as well as on the northern coast of Africa, while the southern race (B. s. capensis) is endemic to parts of southern Africa. It is a secretive bird, seldom seen in the open as it prefers to skulk in reed beds and thick vegetation near water bodies. Its presence is apparent in the spring, when the booming call of the male during the breeding season can be heard. It feeds on fish, small mammals, fledgling birds, amphibians, crustaceans and insects.

The nest is usually built among reeds at the edge of bodies of water. The female incubates the clutch of eggs and feeds the young chicks, which leave the nest when about two weeks old. She continues to care for them until they are fully fledged some six weeks later.

With its specific habitat requirements and the general reduction in wetlands across its range, the population is thought to be in decline globally. However the decline is slow, and the International Union for Conservation of Nature has assessed its overall conservation status as being of "least concern". Nevertheless, some local populations are at risk and the population of the southern race has declined more dramatically and is cause for concern. In the United Kingdom it is one of the most threatened of all bird species.

Taxonomy and etymology

This species was first described as Ardea asteria sive stellaris as early as 1603 by Ulisse Aldrovandi in his Ornithologiae. In 1660 the ornithologist Thomas Browne referred to it as Ardea stellaris botaurus and then the Swedish naturalist Carl Linnaeus in his Systema Naturae of 1758 named it again as Ardea stellaris. It is placed in the subfamily Botaurinae, and its closest relatives are the American bittern (Botaurus lentiginosus), the pinnated bittern (Botaurus pinnatus) and the Australasian bittern (Botaurus poiciloptilus). Two races of Eurasian bittern are recognised; the nominate subspecies B. s. stellaris has a palearctic distribution and occurs across a broad swathe of Europe, North Africa and Asia, while the other subspecies, B. s. capensis, occurs only in southern Africa. The name capensis was used for species found in the Afrotropics for which no exact range was known.

The generic name Botaurus was given by the English naturalist James Francis Stephens, and is derived from Medieval Latin butaurus, "bittern", itself constructed from the Middle English name for the bird, botor. Pliny gave a fanciful derivation from Bos (ox) and taurus (bull), because the bittern's call resembles the bellowing of a bull. The species name stellaris is Latin for "starred", from stella, "star", and refers to the speckled plumage. Most of these were onomatopoeic colloquial names for the bird; the call was described as "bumping" The powerful bill is greenish-yellow with a darker tip to the upper mandible. The eye has a yellow iris and is surrounded by a ring of greenish or bluish bare skin. The legs and feet are greenish, with some yellow on the tarsal joint and yellow soles to the feet. Juveniles have similar plumage to adults but are somewhat paler with less distinct markings.

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Great bittern (Botaurus stellaris) in flight Vadu.jpg

Great bittern (Botaurus stellaris) in flight Vadu 3.jpg

Great bittern (Botaurus stellaris) in flight Vadu 2.jpg

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Distribution and habitat

The breeding range of B. s. stellaris extends across temperate parts of Europe and Asia from the British Isles, Sweden and Finland eastwards to Sakhalin Island in eastern Siberia, Korea and Hokkaido Island in Japan. The bird's northern extent of occurrence is around 57°N in the Ural Mountains and 64°N in eastern Siberia. Its southern limit is the Mediterranean Sea, the Black Sea, Iran, Afghanistan, Kazakhstan, Mongolia and Hebei Province in northern China. Small resident populations also breed in Morocco, Algeria and Tunisia. The southern race has suffered catastrophic decline during the 20th century due to wetland degradation and, unlike the northern race, is of high conservation concern. In 1997 there were 11 males and by 2007 an estimated 44 breeding pairs, concentrated mainly in Lancashire and East Anglia. In 2021, 228 breeding males were counted in the United Kingdom, an increase of 19 birds since 2019. while bitterns have been attracted to new reed beds in the West Country. After extensive reedbed restoration, nesting and breeding was observed in north Wales, while in 2020, two pairs successfully bred at Newport Wetlands in Gwent, south Wales. These were the first bitterns to breed in the county in some 250 years. In the 21st century, bitterns are regular winter visitors to the London Wetland Centre, enabling city dwellers to view these scarce birds. In Ireland, it died out as a breeding species in the mid-19th century, but in 2011 a single bird was spotted in County Wexford and there have been a number of subsequent sightings.

Booming

The Eurasian bittern is proposed as one of rational explanations behind the drekavac, a creature of the graveyard and darkness originating in south Slavic mythology. It is mentioned in the short story "Brave Mita and Drekavac from the Pond" by Branko Ćopić.

The species is mentioned in George Crabbe's 1810 narrative poem The Borough, to emphasise the ostracised, solitary life of the poem's villain, Peter Grimes:

The Irish poet Thomas MacDonagh translated the Gaelic poem "The Yellow Bittern" ("An Bonnán Buí" in Irish) by Cathal Buí Mac Giolla Ghunna. His friend, the poet Francis Ledwidge, wrote a "Lament for Thomas MacDonagh" with the opening line "He shall not hear the bittern cry".

In the Sherlock Holmes novel The Hound of the Baskervilles by Sir Arthur Conan Doyle, the naturalist Stapleton proposes the boom of a bittern as an explanation for the howl attributed to the mystical hound.

Because of its secretive and skulking nature, it was for long unclear exactly how the bittern produced its distinctive booming call. A Mediaeval theory held that the bittern thrust its beak into the boggy ground of the marsh in which it lived, making its vocalization which was amplified and deepened as it reverberated through the water. A reference to this theory appears in 1476 in Chaucer's The Wife of Bath's Tale, lines 972-73:

Camouflage

The artist Abbott Handerson Thayer argued in Concealing-Coloration in the Animal Kingdom that animals were concealed by a combination of countershading and disruptive coloration, which together "obliterated" their self-shadowing and their shape. However, Thayer's conclusions have been disputed.

The zoologist Hugh Cott, in his classic 1940 study of camouflage, Adaptive Coloration in Animals, cites William Palmer's account of seeing a bittern:

  • Ageing and sexing (PDF) by Javier Blasco-Zumeta & Gerd-Michael Heinze
  • BBC Wildlife Finder – videos and information
  • Bittern – The Atlas of Southern African Birds