Whistling Heron

Overview

The whistling heron (Syrigma sibilatrix) is a medium-sized, often terrestrial heron found across South America, and it is the only species in the genus Syrigma. Classified as Least Concern by the IUCN, this bird benefits from deforestation and some agriculture, making it a successful heron of dry tropical countries comparable to the cattle egret and black-headed heron.

Identification

• Measures 53 to 64 cm in length with short, greenish legs and a pink bill that has a blue to violet base and black distal third.
• Adults have blue-gray upperparts and white feathers on the head, neck, and breast stained gold to buff, while the southern subspecies features a black crown and crest, unlike the slate-gray crown of the northern subspecies.
• Flight is characterised by fast, duck-like wingbeats and a neck that is not fully retracted, revealing conspicuous white lower back, belly, and tail.
• Named for its loud, flute-like whistled call described as 'kleeer-er' or 'wueeee', often issued in a series, with a harsh 'quah-h-h' alarm call.

Habitat

The species inhabits seasonally flooded savannas, often in drier grassy situations or open waterlogged terrain up to 500 m in elevation, and shows a preference for areas where open spaces are mixed with woodlots for roosting. It is found in the Llanos and Orinoco basin of Colombia and Venezuela, as well as eastern Bolivia, Paraguay, western and southern Brazil, Uruguay, Chile, and northeastern Argentina, with recent records suggesting a northward and eastward range expansion in Brazil. It readily adapts to human-altered environments such as pastures and roadsides, frequently perching on fenceposts.

Diet

This heron consumes a wide range of small dryland and marsh animals, occasionally pirating prey from other birds such as aplomado falcons. It forages by holding still, walking slowly, or actively running after prey and catching flying insects like dragonflies from a standing position. It typically feeds alone or in pairs but may gather in groups of up to 100, particularly before roosting.

Did you know?

Unlike most herons that nest in colonies, the whistling heron nests alone, sometimes in exotic trees, and provides post-fledging care to its young. Juveniles are notable for begging for food by hissing with their wings drooped.