Least Bittern

Ixobrychus exilis

Order CICONIIFORMES - Family ARDEIDAE

Menu

1. Cool Facts
2. Description
3. Similar Species
4. Sound
5. Range
6. Habitat
7. Food
8. Behavior
9. Reproduction
10. Conservation Status
11. Other Names

A tiny heron, furtive and surpassingly well camouflaged, the Least Bittern is one of the most difficult North American marsh birds to spot. Despite its inconspicuousness, however, the species can be rather common within appropriate habitat in its breeding range.

Cool Facts

• Thanks to its habit of straddling reeds, the Least Bittern can feed in water that would be too deep for the wading strategy of other herons.

• When alarmed, the Least Bittern freezes in place with its bill pointing up, turns its front and both eyes toward the source of alarm, and sometimes sways to resemble wind-blown marsh vegetation.

• The Least Bittern and the American Bittern often occupy the same wetlands, but may have relatively little interaction because of differences in foraging habits, preferred prey, and timing of breeding cycles. The Least Bittern arrives on its breeding grounds about a month after the American Bittern, and leaves one or two months earlier.

• John James Audubon noted that a young captive Least Bittern was able to walk with ease between two books standing 1.5 inches (4 cm) apart. When dead, the bird's body measured 2.25 inches (5.7 cm) across, indicating that it could compress its breadth to an extraordinary degree.

Description

• Size: 28-36 cm (11-14 in)
• Wingspan: 41-46 cm (16-18 in)
• Weight: 51-102 g (1.8-3.6 ounces)

• Tiny heron.
• Long neck.
• Long bill.
• Crown and back black or dark brownish.
• Neck and sides warm orange-brown.
• Front of neck and chest striped orange and white.

• Large golden patches in wings visible in flight.
• White lines along sides of dark back.
• Bill yellow with dark upper edge.
• Legs pink at top, green in front, yellow behind.
• Eyes pale yellow.
• Often seen at the base of cattails at the edge of the water.
• Cory's Least Bittern, a very rare dark morph, has dark brown instead of orange-brown on neck, sides, and front.

Sex Differences

Sexes similar, but females have more muted colors, especially in the black on the mantle and crown.

Immature

Similar to adult female, with paler and browner crown.

Similar Species

• Green Heron is much larger, with completely dark wings and a dark bill.
• American Bittern is huge in comparison, and is colored entirely in muted browns.
• Rails lack bright wing patches and have shorter necks.

Sound

Song a low "coo-coo-coo." Contact call is flat and quack-like.

»listen to songs of this species

Range

Summer Range

Breeds throughout the eastern and central United States and southern Ontario from coastal Maine to Florida, and westward to the eastern Dakotas and central Texas. Also in scattered localities in western United States, in Mexico, Caribbean, and Central and South America.

Winter Range

Winters from the mid-Atlantic seaboard to south Florida and southward.

Habitat

Freshwater or brackish marshes with tall emergent vegetation.

Food

Small fish and insects.

Behavior

Foraging

Stalks along reeds, sometimes next to rather deep water, or climbs on reed stalks, and strikes downward into water with bill.

Reproduction

Nest Type

A platform of marsh vegetation with a canopy made by pulling tall marsh plants over and crimping them in place. Placed in dense, tall stands of vegetation.

Egg Description

Pale blue or green.

Clutch Size

Usually 4-5 eggs. Range: 2-7.

Condition at Hatching

Covered in down, rusty brown on back, whitish below; able to sit and hold head up only for brief periods.

Conservation Status

Difficult to survey, so few data available. Loss of wetland habitat and the encroachment of exotic species of marsh vegetation may pose a threat.

Other Names

Blongios minute, Petit Blongios, Petit Butor (French)
Ardeola, Garza enana, Garcilla (Spanish)

Sources used to construct this page:

1. Audubon, J. J. 1840. Birds of North America. First Octavo Edition.
2. Gibbs, J. P., F. A. Reid, and S. M. Melvin. Least Bittern (Ixobrychus exilis). In The Birds of North America, No. 17 (A. Poole, P. Stettenheim, and F. Gill, eds.). Philadelphia: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.