Ardea stellaris Linnaeus, 1758, Sweden. Two subspecies.
OTHER COMMON NAMES
English: Great bittern, common bittern; French: Butor йtoilй German: Rohrdommel; Spanish: Avetoro Comъn.
A thick-necked, medium-sized, golden brown heron with a black head and moustache. Length is 25–31 in (64–80 cm); weight is 1.9–4.3 lb (0.9–1.9 kg). Its back is cryptic mottled and mottled. It is the largest of the four species of large bitterns. Males are significantly larger than females.
Occurs in the Old World temperate and tropical zones of Europe, Asia, and Africa.
Occurs in densely vegetated wetlands. During the breeding season, it is found only in reed beds characterized by dense plants, stable shallow flooding, and with intermittent clearings or channels. During the nonbreeding season, it uses more varied and open aquatic habitats such as small ponds, gravel pits, wet grassy meadows, ditches, tall rice fields, fish ponds, floating leafed plant beds, and sewage lagoons.
Hunts by walking with stealth in a crouched posture, the bill pointed forward, and the feet lifted high with each step. Moves about by climbing over the emergent stems, using long toes to grasp the stems. Can hold a concealing
, called the bittern posture, for hours. In this posture, it raises its bill to the sky and peers directly forward, swaying as if in the breeze and turning slowly to keep eyes on a moving intruder. A solitary feeder that fiercely defends its feeding and nesting area during breeding using its booming call. The call consists of two to four deep, resonant booms preceded by a few short grunts or pumps, sometimes accompanied by clappering the bill. It is aggressive in physically defending its site, and also flies to supplant intruders and fights in the air, even to the death.
FEEDING ECOLOGY AND DIET
Feeds at the edge of emergent reeds and open water, such as along a pool, channel, or ditch, avoiding unflooded ground. Primarily feeds in the morning and evening but is known to hunt during the day and at night. Fish, amphibians, and insects usually dominate the diet. Small mammals, birds, and snakes are also taken.
Nests solitarily in spring and summer or in the rainy season in the tropics. Non-migrating birds begin to call as early as late winter. Nest is a pad of matted reeds and other marsh vegetation that is built by the female. A polygamous species, males may have up to five mates, each of which has a nest within the male’s territory. Eggs are olive brown with spotting. The normal clutch is four to five eggs; range is three to seven. Incubation begins immediately, and the range of hatching dates for a large clutch may stretch over two weeks. Only the female incubates, lasting 25–26 days. Young can leave the nest after about two weeks and fledge at 50–55 days.
The Eurasian bittern was formerly widespread and abundant, but suffered significant population changes. In Europe, it declined steadily since as early as the nineteenth century, being extirpated from England in 1868. It began a comeback through Europe in early 1900s, increased into the 1960s and then began a second decline, in some cases very rapidly. It is now regionally Vulnerable in Europe. The southern African population is even more at risk, given its rapid decline over the past several decades.
SIGNIFICANCE TO HUMANS
The Eurasian bittern occurs in reed beds and marshes throughout its range. It is a skulking species that stays hidden, at least during the day. It nonetheless is well known owing to its booming call. This call has entered into folklore wherever large bitterns occur, generally as a harbinger of evil.
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