A Great Blue Heron Quietly Vocalizing February 10, 2019, at Turtle Pond in Central Park, New York City. "Great Blue Herons are most vocal on the breeding grounds, where they greet their partner with squawking roh-roh-rohs in a “landing call” when arriving at the nest. A disturbance can trigger a series of clucking go-go-gos, building to a rapid frawnk squawk that can last up to 20 seconds. If directly threatened, birds react with a screaming awk lasting just over 2 seconds." The Cornell Lab of Ornithology