An odd but not uncommon sound in the night is the flat, barking “quork” of the Black-crowned Night Herons as they fly to their nighttime hunting grounds along ponds, salt-water marshes and slow-moving streams. The Black-crowned Night Heron is very stout or chunky, standing about two-feet tall. It has a large head, short neck and relatively short, yellow legs.
The immature herons are grey-brown with heavy streaking, creamy-white spots on their wings and a yellowish bill. Adults are striking with their jet-black cap, bill and back. They have large red eyes. Their cheeks and underside are white; wings and tail are gray. Breeding adults have two beautiful long, white, skinny plumes of feathers trailing from the back of their heads. Their feet can turn a brilliant red during courtship.
During the day, they typically roost communally in dense stands of trees or brush, sleeping with their bill tucked in their breast feathers. When night falls, they spread into almost every kind of aquatic habitat to hunt amphibians, reptiles, fish, invertebrates, small mammals and birds. In some areas they are known to be significant predators of ducklings and rails. Black-crowned Night Herons are expert at still-fishing. They wait motionless for their prey then strike them with their heavy, sharply-pointed bill. By feeding at night they don’t compete with other herons and egrets. When Black-crowned Night Herons feed by day they are often attacked by other herons and egrets.
Black-crowned Night Herons nest colonially in almost every kind of habitat: from pine groves to cattail marshes, willows, orchards and city parks. In courtship, the male bows to the female. He stretches his neck and erects his breast feathers and the plumes on his back. The female responds similarly. The pair will rub bills and smooth each other’s feathers. The male collects the nesting material for the female, who builds the nest of loose sticks with fine inner lining. Both parents incubate the three to five bluish-green eggs for two weeks and together care for the young for six to seven weeks.