American Bittern

American Bittern
Botaurus lentiginosus

Pelecaniformes Order – Ardeidae Family

INTRODUCTION:
The American Bittern was first described by the English clergyman Thomas Rackett in 1813, from a vagrant specimen captured in S England.  
This monotypic species resembles the Eurasian Bittern but it is slightly smaller, with speckled rather than barred plumage. This solitary bird is usually well-hidden among the marshy vegetation and difficult to find. It is more often heard than seen, when the male gives its typical booming call while holding the head upwards and forwards.
The American Bittern is found in North America and breeds in southern Canada. It migrates southwards after breeding and spends the winter in southern USA, Caribbean Islands and Mexico.
The American Bittern is not globally threatened, although the population is slightly declining in North America, probably due to loss of marshy habitats.

DESCRIPTION OF THE BIRD:
Biometrics:
Length: 56-85 cm
Wingspan: 105-125 cm
Weight: 372-1072 g (average 600 g)   

The American Bittern is a stocky Ardeidae. It has cryptically coloured plumage, well-adapted to the life in marshy vegetation.
On the upperparts, hindneck, back and wings are brown and finely freckled, speckled and vermiculated grey and black. The flight-feathers are black with rufous tips.

On the underparts, chin and throat are white, the latter is streaked rufous, and mostly buff on the breast. There are white tufts on breast sides, well visible during the displays. On the underwing, the coverts are pale rufous while the flight-feathers are greyish-white. Belly and vent are buffy-white.

On the head, the crown is uniformly rusty-brown. The facial skin is pale yellow and contrasts with a dark line across the lores. The sides of the face are brown. We can see a black moustachial stripe contrasting with the white chin.
The pointed bill is yellowish, with greyish-black culmen and tip. The eyes are yellow. Legs and feet are yellow-green.

The female has similar appearance, but she is slightly smaller than male.
The juvenile lacks the black stripe on neck sides.

RANGE:
The American Bittern breeds in S and C Canada, from British Columbia, N along the Hudson Bay and E to Newfoundland, then S through USA, and formerly in C Mexico.
It winters in southern USA, in California, Gulf Coast and S Atlantic coast, also in Mexico and Caribbean Islands.  

HABITAT:   
The American Bittern frequents marshes and lakes with reeds. It breeds mainly in large freshwater marshes and shallow wetlands with tall vegetation including cattails, sedges and grasses, and also in areas of open shallow water.
In winters in similar habitat and also frequents salt and brackish coastal marshes. It can be seen occasionally feeding in dry grassy areas.

CALLS AND SONGS: SOUNDS BY XENO-CANTO
The American Bittern is known for the male’s call. It gives a unique, far-carrying booming sound described as “oong, kack, oonk” with louder final note. This call is sometimes preceded by a series of soft gulping sounds.
A low “kok-kok-kok” is given in flight and in alarm. Nasal sounds can be heard during the copulation.

BEHAVIOUR IN THE WILD:
The American Bittern feeds primarily on fish such as catfish, eels, perch… and various other aquatic prey including aquatic insects, frogs, tadpoles, crustaceans, salamanders and water snakes. But in drier areas, it also catches rodents, especially voles.

It typically hunts by standing motionless at water edge, or by walking slowly, stopping suddenly to catch a passing prey with the bill. It is usually more active at dawn and dusk, but it may forage at any time by day or at night.

During the breeding season, the male utters its booming calls to defend the territory. When the female returns to the breeding areas, the male displays while calling loudly. It holds the head low with the bill close to the ground and displays the white tufts by fluffing out these feathers on the sides of the breast. The male may mate with two or three females, but it is more often monogamous.

The American Bittern is migratory and performs extensive post-breeding dispersal. It migrates southwards in September/November, and returns in extreme north in February/March to mid-May. It migrates alone or in small groups, usually at night.
This species is vagrant, including in parts of Western Europe such as Iceland, Faeroes and British Islands.
The flight is strong and direct, with deep, rapid wingbeats.  

This one was observed

in Cheshire (UK)

REPRODUCTION OF THIS SPECIES:  
The laying occurs between April and July throughout the range.
The American Bittern is territorial and usually solitary nester. The female chooses the nest-site and builds a platform low over water, in dense emergent vegetation. The nest is made with reeds, sedges, cattails and other aquatic plants, and it is lined with softer vegetation.

She lays 3-5 to 2-7 pale brown/olive-buff eggs, and incubates alone during 24-28 days. At hatching, the chicks have yellowish-olive down, darker below. They are fed by the female by regurgitation or partly-digested items. They leave the nest one or two weeks after hatching, but they remain in the surrounding and still depend on the female for food until four weeks of age.

PROTECTION / THREATS / STATUS:
The American Bittern is threatened by loss of habitat in the southern part of the breeding range. It depends heavily on large marshes and is vulnerable to acid rains that may reduce the food resources in some areas.
The population is suspected to be slowly declining in some regions, but the species is not globally threatened and currently evaluated as Least Concern.