The American bittern (Botaurus lentiginosus) is a species of wading bird in the heron family. It has a Nearctic distribution, breeding in Canada and the northern and central parts of the United States, and wintering in the U.S. Gulf Coast states, all of Florida into the Everglades, the Caribbean islands and parts of Central America.

It is a well-camouflaged, solitary brown bird that unobtrusively inhabits marshes and the coarse vegetation at the edge of lakes and ponds. In the breeding season it is chiefly noticeable by the loud, booming call of the male. The nest is built just above the water, usually among bulrushes and cattails, where the female incubates the clutch of olive-colored eggs for about four weeks. The young leave the nest after two weeks and are fully fledged at six or seven weeks.

The American bittern feeds mostly on fish but also eats other small vertebrates as well as crustaceans and insects. It is fairly common over its wide range, but its numbers are thought to be decreasing, especially in the south, because of habitat degradation. However the total population is large, and the International Union for Conservation of Nature has assessed its conservation status as being of "Least Concern".

Description

left|thumb|American bittern, feathers puffed, [[Nisqually National Wildlife Refuge]]

The American bittern is a large, chunky, brown bird, very similar to the Eurasian bittern (Botaurus stellaris), though slightly smaller, and the plumage is speckled rather than being barred. It is in length, with a wingspan and a body mass of .

The crown is chestnut brown with the centers of the feathers being black. The side of the neck has a bluish-black elongated patch which is larger in the male than in the female. The hind neck is olive, and the mantle and scapulars are dark chestnut-brown, barred and speckled with black, some feathers being edged with buff. The back, rump, and upper tail-coverts are similar in color but more finely speckled with black and with grey bases to the feathers. The tail feathers are chestnut brown with speckled edges, and the primaries and secondaries are blackish-brown with buff or chestnut tips. The cheeks are brown with a buff superciliary stripe and a similarly colored mustachial stripe. The chin is creamy-white with a chestnut central stripe, and the feathers of the throat, breast, and upper belly are buff and rust-colored, finely outlined with black, giving a striped effect to the underparts. The eyes are surrounded by yellowish skin, and the iris is pale yellow. The long, robust bill is yellowish-green, the upper mandible being darker than the lower, and the legs and feet are yellowish-green. Juveniles resemble adults, but the sides of their necks are less olive.

Taxonomy

The American bittern was first described in 1813 by the English clergyman Thomas Rackett from a vagrant individual he examined in Dorset, England. Pliny gave a fanciful derivation from (ox) and (bull), because the bittern's call resembles the bellowing of a bull. The species name lentiginosus is Latin for "freckled", from lentigo (freckle), and refers to the speckled plumage. In his book on the common names of American birds, Ernest Choate lists "bog bumper" and "stake driver". Other vernacular names include "thunder pumper", "bog bull", "bog thumper", "mire drum", and "water belcher".

Distribution and habitat

Its range includes much of North America. It breeds in southern Canada as far north as British Columbia, the Great Slave Lake and Hudson Bay, and in much of the United States and possibly central Mexico. It migrates southward in the fall and overwinters in the southern United States of the Gulf Coast region, most notably in the marshy Everglades of Florida, the Caribbean Islands and Mexico, with past records also coming from Panama and Costa Rica. As a long-distance migrant, it is a very rare vagrant in Europe, including Great Britain and Ireland. It is an aquatic bird and frequents bogs, marshes and the thickly-vegetated verges of shallow-water lakes and ponds, both with fresh and brackish or saline water. It sometimes feeds out in the open in wet meadows and pastures.

Behavior

thumb|American bittern attempting to hide

right|thumb|American bittern (dead center, head extended) hiding in tall grass, [[Wakulla Springs State Park ]]

The American bittern is a solitary bird and usually keeps itself well-hidden and is difficult to observe. It usually hunts by walking stealthily in shallow water and among the vegetation, stalking its prey, but sometimes it stands still in ambush. If it senses that it has been seen, it remains motionless, with its bill pointed upward, its cryptic coloration causing it to blend into the surrounding foliage. It is mainly nocturnal and is most active at dusk. More often heard than seen, the male bittern has a loud, booming call that resembles a congested pump and which has been rendered as "oong, kach, oonk".

Like other members of the heron family, the American bittern feeds in marshes and shallow ponds, preying mainly on fish but also consuming amphibians, reptiles, small mammals, crustaceans and insects. It is a territorial bird and has a threat display which involves slowly erecting long, white, previously-concealed, plumes on its shoulders, to form wing-like extensions that nearly meet across its back, resembling a ruff. The bird then stands still in a threatening posture, or stalks the intruder in a crouching position, with its head retracted and a gliding gait. It is also protected under the Canadian Migratory Birds Convention Act of 1917 to which both Canada and the United States are signatories.

References and notes

Further reading

  • National Geographic Society (2002). Field Guide to the Birds of North America. National Geographic, Washington DC.
  • American Bittern – Cornell Lab of Ornithology
  • American bittern – Botaurus lentiginosus – USGS Patuxent Bird Identification InfoCenter
  • American Bittern Botaurus lentiginosus – ENature.com