Pilherodius
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The capped heron (''Pilherodius pileatus'') is a water bird endemic to the
neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...
, inhabiting rainforest from the center of Panama to the south of Brazil.Ridgely, R. S., & Gwynne, J. A. (1989). ''A guide to the birds of Panama: with Costa Rica, Nicaragua, and Honduras''. Princeton University Press. It is the only species of the genus ''Pilherodius'', and one of the least known of the heron family,
Ardeidae The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...
. It is superficially similar to the group of the night herons, but is active during daytime or at twilight.Payne, R. B., & Risley, C. J. (1976). ''Systematics and evolutionary relationships among the herons (Ardeidae)''. Museum of Zoology, University of Michigan.


Taxonomy

The capped heron was described by the French polymath
Georges-Louis Leclerc, Comte de Buffon Georges-Louis Leclerc, Comte de Buffon (; 7 September 1707 – 16 April 1788) was a French naturalist, mathematician, cosmologist, and encyclopédiste. His works influenced the next two generations of naturalists, including two prominent ...
in 1780 in his ''Histoire Naturelle des Oiseaux'' from a specimen collected in Cayenne,
French Guiana French Guiana ( or ; french: link=no, Guyane ; gcr, label=French Guianese Creole, Lagwiyann ) is an overseas department/region and single territorial collectivity of France on the northern Atlantic coast of South America in the Guianas. ...
. The bird was also illustrated in a hand-coloured plate engraved by
François-Nicolas Martinet François-Nicolas Martinet (1731 - 1800) was a French engineer, engraver and naturalist. Martinet engraved the plates for numerous works on natural history, especially ornithology. Notable in particular are those for ''l'Ornithologia, sive Synop ...
in the ''Planches Enluminées D'Histoire Naturelle'' which was produced under the supervision of
Edme-Louis Daubenton Edme-Louis Daubenton (12 August 1730 – 12 December 1785) was a French naturalist. Daubenton was the cousin of another French naturalist, Louis Jean-Marie Daubenton. Georges-Louis Leclerc, the Comte de Buffon engaged Edme-Louis Daubenton to su ...
to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist
Pieter Boddaert Pieter Boddaert (1730 – 6 May 1795) was a Dutch physician and naturalist. Early life, family and education Boddaert was the son of a Middelburg jurist and poet by the same name (1694–1760). The younger Pieter obtained his M.D. at the Univers ...
coined the binomial name ''Ardea pileata'' in his catalogue of the ''Planches Enluminées''. The capped heron is now the only species placed in the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
''Pilherodius'' that was erected by the German naturalist Ludwig Reichenbach in 1853. The genus name combines the
Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic p ...
πιλος ''pilos'' "cap" and ερωδιος ''erōdios'' meaning "heron". The specific epithet ''pileatus'' is Latin for "capped". There is little known about the relationship of ''P. pileatus'' with the other species of the family
Ardeidae The herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera ''Botaurus'' and ''Ixobrychu ...
, because of its lack of inclusion in genetic studies. With the little information available it is believed that its closest living relative is the whistling heron (''Syrigma sibilatrix'').


Description

This species is very distinct from other herons, being the only one with a blue beak and face, and a black crown. The belly, chest, and neck are covered with yellowish-white or light-cream feathers. The wings and back are covered with white feathers. Three to four white long feathers extend from the black crown.Wetmore, A., Pasquier, R. F., & Olson, S. L. (1965). ''The Birds of the Republic of Panama: Tinamidae (tinamous) to Rynchopidae (skimmers)'' (Vol. 1). Smithsonian Institution.Hancock, J., Elliott, H. F., Hayman, P., & Gillmor, R. (1978). ''Herons of the world''. London Editions. No sexual dimorphism in color or brightness has been noted.Kushlan, J. A., & Hancock, J. A. (2005). ''Herons''. OUP Oxford. The body length of an adult varies between 510 and 590 mm, the wing chords between 263 and 280 mm, the tail between 95 and 103 mm, and the tarsus between 92 and 99 mm. The weight of an adult varies between 444 and 632 g.Willard, D. E. (1985). Comparative feeding ecology of twenty-two tropical piscivores. ''Ornithological Monographs'', 788-797. The juveniles are very similar to the adults. They only differ in body length and that the white feathers are slightly grey.


Distribution

The capped heron is endemic to the
neotropics The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...
and almost exclusive to rainforest.Stotz, D. F., Fitzpatrick, J. W., Parker III, T. A., Moskovits, D. K., & Snow, D. (1996). ''Neotropical birds: ecology and conservation'' (No. 598.298 N438). Chicago: University of Chicago Press. It is present in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Panama, Paraguay, Peru, Suriname, and Venezuela.BirdLife International 2009. ''Pilherodius pileatus'' In: 2010 IUCN Red List of Threatened Species It inhabits low lands up to 900 m above sea level, though in Venezuela it is only found below 500 m,Hilty, S. L. (2002). ''Birds of Venezuela''. Princeton University Press. and in Ecuador below 400 m.Ridgely, R. S., & Greenfield, P. J. (2001). ''The birds of Ecuador: status, distribution, and taxonomy'' (Vol. 1). Cornell University Press. Although there are no migrations registered to this species and it is believed that is sedentary, there may be seasonal movements in Darien, Panama.Hancock, J., & Kushlan, J. A. (2010). ''The herons handbook''. A&C Black.


Habitat

The capped heron normally inhabits swamps and ditches in wet grasslands or rainforests. Sometimes it can venture into deeper ponds and rivers. They prefer to forage on the shore or in floating vegetation,Kushlan, J. A., Hancock, J. A., Pinowski, J., & Pinowska, B. (1982). Behavior of Whistling and Capped Herons in the seasonal savannas of Venezuela and Argentina. ''Condor'', 255-260. but have also been observed in trenches of coffee plantations and flooded rice fields.


Feeding

Capped herons hunt mainly for fish, but also aquatic insects and larvae, tadpoles, and frogs. Fish taken as prey tend to be between 1 and 5 cm long. The insects are hunted in the nearby vegetation along the river or pond, and the fish in the shallow waters. In a typical hunting sequence the heron will stand erectly searching for potential prey; after locating it they will crouch slowly and extend their neck; finally they will introduce their beak into the water at a great speed to catch the prey. The frequency of success observed is 23%. They can also use the same sequence while walking in the shallows. They usually walk slowly, covering the same area repeatedly pausing for a few seconds, then slowly moving one foot to take a new step. There are reports of individuals doing aerial hunting, peaking, gleaning, foot paddling, dipping, swimming feeding, and bill-vibrating. Capped herons move frequently between feeding sites, sometimes flying up to 100m. They may be crepuscular, but have been observed foraging during broad daylight, unlike the night-herons.Haverschmidt, F. (1958). The feeding habits of the Capped Heron (Pilherodius pileatus). ''The Auk'', ''75''(2), 214-214. They usually hunt solitarily.Ogden, J. C., & Thomas, B. T. (1985). A colonial wading bird survey in the Central Llanos of Venezuela. ''Colonial Waterbirds'', 23-31.


Behaviour


Territoriality

Capped herons are strongly territorial; the same bird may be seen at a foraging site for weeks at a time. One capped heron was seen chasing another away from a foraging site, until the other bird settled high in a tree.


Interspecific and intraspecific behaviour

The capped heron is normally solitary, although there are cases where they have been found in couples or groups. Birds may be seen with other species such as snowy egrets (''Egretta thula'') and scarlet ibis (''Eudocimus ruber''), however other studies have found that they avoid large mixed-species flocks, appearing in fewer than 1% of 145 observed feeding aggregations. Capped herons appear to be submissive to great egrets (''Ardea alba''), but dominant to snowy egrets (''Egretta thula'') and striated herons (''Butorides striatus'').


Reproduction

There is very little known about the reproduction of this species. Captive breeding in Miami, USA indicates that a female may lay 2-4 dull white eggs, incubation lasts 26–27 days, and that the chick has white down. However, these captive individuals failed to have any young survive, possibly due to a deficient diet or abnormal behavior in the adults. Based on birds with a similar biology, it is likely that they maintain family groups and care for young even after the young have reached the fledgling stage. There may be a two-cycle breeding pattern, with northern and southern populations breeding at different times of the year.


Conservation

This species has an extremely large range, and hence does not approach the thresholds for a Vulnerable rating under the range-size criterion. The population size has not been quantified, and the trend is not known, but it is not believed to approach the thresholds for Vulnerable under the population size or trend criteria. For these reasons the species is evaluated as Least Concern. Nevertheless, it occurs in very low densities and is considered "rare" in Ecuador, Colombia, Venezuela, and Panama. The capped heron appears to be adaptable and may be expanding its use of man-made habitats. People have found some individuals in pools along the Transamazonian Highway Brasil.Sick, H. (1993). ''Birds in Brazil''. Princeton Univ. Press, Princeton, New Jersey. However, given that it is mainly a riverine forest species, the loss of this habitat due to logging and conversion of forest to pasture might pose long-term threats.


References


External links

{{Taxonbar, from=Q217951 capped heron capped heron Birds of Panama Birds of Colombia Birds of Venezuela Birds of the Guianas Birds of the Amazon Basin Birds of Brazil Birds of Trinidad and Tobago capped heron Taxonomy articles created by Polbot capped heron