The Boat-billed Heron & Call – Costa Rica

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boat billed heron birds

The boat-billed heron (Cochlearius cochlearius), colloquially identified as the boatbill, is an atypical member of the heron family & was formerly placed in a monotypic species, the Cochlearidae.

It lives in mangrove marshes from Mexico south to Peru & Brazil. It is a nocturnal bird & breeds semi-colonially in mangrove trees, laying two to four bluish-white eggs in a twig nest.

Boat Billed Heron Description

The boat-billed heron grows to around 54 cm (21 in) long. Adults are pale grey to white, with chestnut-colored abdomens & black thighs.

The large, broad, scoop-like bill, which gives rise to the species’ name, is mostly black and blue in some species.

Boat billed heron birds

The bird is adorned with a crest used in mate attraction as it is more prominent in males. Males & females are similar in appearance, the main exceptions being that females are slightly smaller, grayer in colour, & have shorter crests than males.

Newly hatched chicks have green-yellow skin, with their upperparts cloaked in gray down feathers. Their upper bill is black, & they have green-yellow legs. Immature herons are darker in colour than adults & lack a crest.

Boat Billed Heron Distribution & habitat

Boat-billed herons range from Mexico to Brazil, Peru & northeastern Argentina. They are nonmigratory birds that favour living in seasonal lagoons & estuaries & nest in mangroves.

Boat billed heron birds

Boat Billed Heron Behaviour & Ecology

Boat Billed Heron Breeding

Boat-billed herons reproduce during the rainy season & have been recorded as breeding two clutches during this time, yielding their first clutch in February during the conclusion of the dry season.

Their clutch sizes vary from two to four eggs, including more eggs being laid during the first nesting season than the second. They usually nest in colonies but have been seen nesting solitarily.

Human disturbance can reduce reproductive success, as herons tend to avoid human association & will leave nests if necessary.

Boat Billed Heron Call

Boat Billed Heron Food & Feeding.

What do Boast Billed herons Feed On?

Boat-billed herons feed on shrimp & small fish such as Dormitator latifrons, a variety of sleeper goby.

Boat billed heron birds

They tend to hunt in vegetative streams, shallow water, & lagoons. When hunting in streams, they use low-hanging twigs & mangrove roots to reach over the water.

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In ponds, they will stroll into the water up to 10 cm (4 in) deep or search near the water’s edge.

To catch prey, they will lunge at fish or shovel the surface of the water with their bills that are uniquely shaped for this way of capture.

They have also been observed using two different feeding techniques; standing & slowly hunting prey or disturbing the water & chasing prey.

Boat-billed herons will hunt nocturnally & have been seen leaving the roost 30 minutes after sundown to hunt and feed.

They have also been observed that they do not feed when a light origin is present such as daylight, moonlight, or artificial light.

One study hypothesised that to search for food in the dark & in shallow, murky water, their bills are sensitive to touch, which helps them feel for their prey.

Boat-billed Heron Habitat

National Park Tortuguero, Costa Rica

The massive broad scoop-like bill, which gives rise to this species’ title, is mainly black. Immature birds have mostly brown upperparts & brown-tinged whitish underparts & lack the crest.

This species feeds on fish, water snakes, mice, crustaceans, eggs, insects, & amphibians. Its calls include a deep croak & a high-pitched pee-pee-pee.

Boat billed heron birds

The Boat-Billed Heron (Cochlearius cochlearius) ranges from Mexico to West Ecuador, North Argentina & Bolivia.

It is seen in wooded riverbanks, estuaries, ponds & swamps, & mangroves. Its size is 51 cm (20 inches), & its weight is 600 g.

This stocky bird has a big head with large & dark eyes. By day roosts in groups of up to 50 in trees, at nigh solitary when fishing.


Further Reading

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