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).