Habitat and Range: Native to South America

Whistling Herons are native to South America, where they are primarily found across a wide range that includes Brazil, Argentina, Paraguay, Uruguay, Bolivia, and parts of eastern Peru. Their preferred habitats are typically open grasslands, wetlands, and lightly wooded areas near bodies of fresh water, which provide both food sources and nesting sites. Unlike other herons, they are less reliant on dense, marshy wetlands, which allows them to inhabit various open landscapes and even semi-arid regions.

There are two subspecies with separate geographical distributions.

The Whistling Heron comprises two recognized subspecies, each with distinct geographical distributions:

1. Syrigma sibilatrix sibilatrix: This is the more widespread of the two subspecies, occupying much of the Whistling Heron’s core range in Brazil, Argentina, Paraguay, and Uruguay. This subspecies is marked by its pale plumage and striking blue facial skin, which is particularly vivid during breeding season.

2. Syrigma sibilatrix fostersmithi: The second subspecies, S. s. fostersmithi, is found in the northern regions, particularly in Venezuela and Colombia. This northern subspecies shares similar characteristics but has subtle plumage differences adapted to its specific environment. It tends to be slightly smaller and paler than S. s. sibilatrix.

Although it’s impossible to be sure, most likely the Whisting Heron observed recently on Bonaire is S. s. fostersmithi, from the the northern region of South America–Venezuela or Colombia.

Despite their slight differences, both subspecies share the same whistling call that distinguishes them from other herons and egrets in their range.

Here, on Bonaire, there is not a similar species, so the Whistling Heron is easy to identify.

Movements and Migration: Reaching the Caribbean

Though the Whistling Heron is mostly sedentary and is not considered migratory, it does make some seasonal movements, especially during the dry season when food sources may become scarce in certain areas. These movements are generally short-range, with the birds shifting to wetter areas within their range.

However, in recent years, observations of Whistling Herons on Caribbean islands such as Bonaire have raised interesting questions about their dispersal habits.

While not true long-distance migrants, some individuals may disperse beyond South America during certain seasons. Bonaire, along with its sister islands of Curacao and Aruba–all located north of Venezuela–have become occasional destinations for these herons, likely due to seasonal dispersal or extended flights in search of suitable habitats.

With Curacao’s and Aruba’s closer proximity to South America, those two islands have been favored with more sightings than have historically occurred here on Bonaire.  But that didn’t matter to three happy birders, after they had enjoyed a welcome sighting of the visiting Whistling Heron!

(Images courtesy of the author.)