BEHAVIOR OF WHISTLING AND CAPPED HERONS IN THE SEASONAL SAVANNAS OF VENEZUELA AND ARGENTINA

Behavior, habitat use, and foraging of the Whistling Heron (Syrigma sibilatrix)a nd Capped Heron (Pilherodiusp ileatus)w ere studied in Venezuela and Argentina. Both foraged primarily alone or in pairs, but Whistling Herons also fed and roosted socially. Whistling Herons nested solitarily, maintained post-fledging associations with young, and appeared to defend feeding territories. They foraged in patches of short grass in wet savannas, especially where water was a few centimeters deep. Capped Herons also foraged in wet savanna, but the edges of streams or ponds seemed to be their preferred habitat. Whistling Herons fed by standing and slow walking, usually in an upright posture. At times they waved their heads in an exaggerated manner. Capped Herons crouched for long periods and walked slowly. Although the basic foraging tactics of the two species were similar, differences support the suggestion that the Capped Heron is a bird of forested streams and ponds while the Whistling Heron is a bird of open savanna. In many ways, the Whistling Heron resembles paleotropical grassland herons

JAMES A. KUSHLAN, JAMES A. HANCOCK et al., Condor 84:255-260