Day: July 20, 2014

capped heron (Pilherodius pileatus)

capped heron (Pilherodius pileatus)

The capped heron (Pilherodius pileatus) is a species of heron in the Ardeidae family. It is in the monotypic genus Pilherodius. It is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Panama, Paraguay, Peru, Suriname, and Venezuela. Its natural habitats are rivers, swamps, and freshwater lakes.

The Capped Heron is the only “all white” heron with a black cap and blue facial skin and bill. Additionally, the feathers of the neck usually are yellowish white or a light cream. The body shape has been described as “rather chunky” (Ridgely and Gwynne 1989), but this is a striking heron that is in no danger of being confused with any other species.The Capped Heron perhaps is most similar to the Whistling Heron (Syrigma sibilatrix)but has much paler upperparts, and a longer bill that is blue, not pink with a dark tip (Sick 1993). In flight, suggests a white Black-crowned Night-Heron (Nycticorax nycticorax) (Ridgely and Gwynne 1989).

Usually quiet. Calls are described as muffled hoots (Lane, in Schulenberg et al. 2007). There are very few recordings of the vocalizations of the Capped Heron. Some muffled hoots can be heard in this recording by Paul Donahue; but the calls of the heron are soft, and almost are drowned out by the rollicking choruses of Black-fronted Nunbird (Monasa nigrifrons), and the longer hoots of Gray-fronted Dove (Leptotila rufaxilla), among other sounds. A woop-woop-woop is given as the bird lowers its head and opens its nuchal crest in front of its mate (Sick 1993). Also may make guttural croaks (Kushlan and Hancock 2005).

Adult: Sexes similar. Crown black, except for a white forecrown. Several (four or five) white plumes extend from the rear of the crown, ca 200-230 in length. Back and wings light gray. Breast, hindneck, and under surface of the wing are light cream-buff. Belly white. Neck is thick for a heron (Kushlan and Hancock 2005).

The creamy or yellowish color of the neck, breast and underwing have been described as an alternate (“breeding”) plumage (Wetmore 1965, Ridgley and Gwynne 1989, Blake1977, Hancock and Elliott 1978). Most ardeids do not have an alternate plumage (Pyleand Howell 2004), however, so it is unlikely that the creamy color is acquired through a molt. The cream colored neck may simply represent the definitive plumage (Odgen andThomas 1985), or perhaps is a result of preening from the patches of powder-down feathers, as it is in the Whistling Heron (Syrigma sibilatrix) (Hancock and Elliott 1978).

Juvenile: Similar to adult, but paler gray above, and with shorter nuchal plumes. Also the crown may be streaked with gray (Ridgely and Gwynne 1989).

Relationships to other herons uncertain. Described by Boddaert in 1783 as Ardea pileata, with a type locality of Cayenne. The monotypic genus Pilherodias was described in 1855 by Bonaparte. Bock (1956) placed the Capped Heron within the subfamily Ardeinea, tribe Nycticoracini, and genus Nycticorax, based on similarities in the adult plumage. However, at the time there were no immature specimens of pileatusfor comparison with the other immature night-herons, which are brown with elongated spots (Bock 1956). This lack of a well defined immature plumage (Wetmore 1965), along with its feeding behavior (Haverschmidt 1958), separates the Capped Heron from the night-herons. Payne and Risley (1976) suggested that morphologically the Capped Heron is more similar to Ardea than to Nycticorax. Unfortunately, recent molecular work on heron relationships has not included the Capped Heron (e.g., Sheldon 1987, Sheldon et al. 1995, Sheldon and Slikas 1997, Sheldon et al. 2000).