The Least Bittern song is a quiet cu-cu-cu (May, NJ).
Here the soft calls of a Least Bittern are just audible over the raucous Green Frogs and Bullfrogs (May, NJ).
A loud kaa-kaa-kaa is often heard later in the breeding season, especially early in the morning (July, NJ).
Least Bittern flight call (4.06am, Oct, PA).
This is a juvenile Least Bittern, still with down on its head, that called almost continuously for the 45 minutes I watched it. Interestingly, it changed its call periodically. These are the 3 different calls I heard (July, NJ).
American Bittern flushed from marsh, flew a short distance (with Swamp Sparrow and American Crow, May, DE).
Presumed American Bittern call in nocturnal flight (2.38am, Oct, PA)
(5.14am, Sep, PA)
Green Herons in flight (Aug, NJ).
Black-crowned Night-Heron (Canada Geese in background, May, NJ).
Black-crowned Night-Herons near roost and calling in flight shortly before dawn (Apr, NJ).
Great Blue Heron (Aug, NJ).
Calls by a flock of Great Egrets (Jul, NJ).
Snowy Egret male courtship call, a bubbling vocalization (May, NJ).