[order] CICONIIFORMES | [family] Ardeidae | [latin] Cochlearius cochlearius | [authority] Linnaeus, 1766 | [UK] Boat-billed Heron | [FR] Savacou huppe | [DE] Kahnschnabel | [ES] Martinete Cucharon | [NL] Schuitbekreiger
The Boat-billed Heron, Cochlearius cochlearius is an unusual member of the Heron family, found in mangrove swamps from Central America to Peru. It used to be known as the Boatbill and classified in a separate family, Cochlearidae. It has now been placed it the family of Ardeidae. Its main feature is its extremely large bill, separating it from all of its congeners.
Boat-billed Heron or Boatbill is a stocky nocturnal heron with very a large beak. Boatbill adult has pale grey upperparts with a broad blackish band across the upper mantle. Flight feathers are grey. Throat is white. Neck is pale pinkish-buff. Underparts from lower breast to vent are dark pinkish-buff. Flanks are black. Short legs and feet are greenish-yellow. The heron has black crown and nape. Head presents long black crest. Forehead is white. Face is creamy to pale pinkish-buff. Large eyes are dark brown and lores are greyish. Bill is remarkably broad and heavy, with about 10 cm long and 5 cm wide. It is blackish or grey on upper mandible, and yellow on lower mandible. This heron has a bare gular pouch. Both sexes are similar. Juvenile has less developed crest. Belly is paler than in adults. It needs three moults to get its adult plumage.
Listen to the sound of Boat-billed Heron
Copyright remark: Most sounds derived from xeno-canto
Latin America : Westcentral Mexico to Northeast Argentina
Boatbill lives in mangroves, freshwater marshes, wooded swamps, shores of lakes and rivers, ponds and streams in wet forest. It may be found from sea level to 800 to 2600 metres of elevation.
Boatbill nests in trees close to the water, in bushes and occasionally in reedbeds. In trees, nest is situated at about 10 meters above the ground. It is a shallow stick nest, built by both male and female. It nests alone or in small colony including other species of water birds. Female lays 3 to 4 pale greenish-blue eggs, finely spotted with red. They are laid at two-day intervals. Incubation lasts about 23 to 28 days, by both parents. It starts with the first egg laid.
Hatches are asynchronous. Altricial chicks are fed by regurgitation by both adults. Sometimes, the youngest chick starves when parents are not able to provide abundant food. Both adults protect the nest against intruders. Nesting period lasts about 6 to 8 weeks. This species produces only one brood per season, but if food resources are abundant, it may produce a second clutch during the dry season, according to the area where it is living.
Boatbill feeds mainly on fish, shrimps and insects, but also on amphibians and small mammals.
copyright: P. de Groot Boersma
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Boatbill is a nocturnal heron. It is solitary feeder at night. It hunts by stabbing preys, or walking slowly in shallow waters. It may run to catch a prey. Large broad bill is used as a spoon, to catch motionless preys. Bill seems to be very sensitive, and it opens at the merest touch. While feeding, Boatbill often utters a frog-like croak.
During the day, Boatbill is perched in trees, among dense foliage in the mangrove. Boatbill is non migratory bird.
During breeding season, Boatbill performs bill-clapping and preening displays while it gives vocal signals. Postures and movements performed during courtship displays are simple and slow. Males often erect and lower their broad crown feathers contrasting strongly with the white forehead. This display is very spectacular. Both sexes clatter vigorously their beaks.
Boatbills are monogamous. Pair may form only for one season, or longer. This species copulates outside the nest, and differs from the other heron species in this behaviour. Breeding time occurs in the rainy season.
To waterproof its feathers, Boatbill has powder down, a kind of feathers that never moult out and grow continuously. So, tips gradually crumble into powder, and the bird spreads this powder over feathers by preening.
Mostly sedentary, with some pist breeding dispersal to south of breeding range.