Black-crowned Night Heron
The Black-crowned Night Heron is a stocky bird, which looks as if it is hunched over with its head tucked down into its shoulders. Its plumage is gray and white with a distinctive black cap and a pair of white plumes that extend from the back of the head. It has a shorter bill, legs, and neck than other herons. Males and females are similar in coloration.
The Black-crowned Night Heron can reach lengths of 23-28 inches with a wingspan of 45 inches. Their body weight can reach up to 2 pounds. Males are slightly larger than the females.
- The long legs of a heron keep it elevated above the water as it wades looking for fish. The toes are long and flexible to help the bird keep its balance on slippery or unsteady surfaces. The heron's long, thin bill is used to quickly grasp the fish it will consume.
Black-crowned Night Herons feed on fish, frogs, crustaceans, small mammals and even the young of other nesting waterbirds. They are nocturnal, which helps them to avoid competition with other herons feeding in the same area during the day. At Cosley Zoo, the Black-crowned Night Heron is fed fish, mealworms, and a vitamin supplement.
Black-crowned Night Herons nest in trees or marshes among the reeds. Their nests are haphazard piles of reeds, sticks or twigs that are reused each breeding season. The female lays three to four bluish-green eggs between February and March and again between June and July. Both parents incubate the eggs and after a period of 24 to 26 days, the downy young will hatch. The parents both feed the nestlings by regurgitating food they have eaten themselves. The young will leave the nest 6-7 weeks later.
Shelter and Space Needs
Black-crowned Night Herons are widely distributed throughout North America. They frequent wooded swamps, ponds, lakes and tropical mangroves. They keep close to water and vegetation such as reeds and trees where they roost and take cover.
The Black-crowned Night Heron lives an average of 3 years in the wild. In captivity, these birds can live up to 17 years.
Importance to Man
Black-crowned Night Herons are strikingly attractive birds and are important members of their ecosystems because they help to control fish populations. Black-crowned Night Herons were placed on the Illinois endangered species list in 1977 and remain there because of their past history of decline, their small population numbers and the threat to their habitats.
- Another name for the Black-crowned Night Heron is the "quark bird" because of the sound it makes as it flies through the night.
- Black-crowned Night Herons sometimes lure food to them by using a technique called "bill vibrating", in which they put their bills in the water and open and close them rapidly to create a disturbance.
- When disturbed by another animal, young Black-crowned Night Herons will regurgitate partially eaten food onto the intruder.
- The digestive acids of these birds are so strong that bones they have consumed simply dissolve in their stomachs!