Recently added to Panama list, the Whistling Heron (Syrigma sibilatrix) is one of the least aquatic members of its family and prefers to forage for large arthropods in open wet grasslands. This bird is named for its distinctive high pitched calls.
Whistling Heron is among the more insectivorous of the herons.
References:
Dean, Sam. 2012. Whistling Heron (Syrigma sibilatrix), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=114716