They Mostly Come Out at Night… Mostly: The Black-crowned Night Herons
For my fellow sci-fi aficionados, it’s a lot prettier than the critter Newt refers to in the Aliens franchise….
Black-crowned Night Herons (Nycticorax nycticorax) are the most widespread herons in the world, and can be found on all continents except Australia and Antarctica. As their name suggests, they’re most active during the dusk and night hours, resting during the day.
Compared to other herons, these guys are small, stocky, short-necked, and short-legged — averaging 23-28″ in length and 25″ in height. The adults sport their descriptive black crown and back, accompanied by light blue-grey wings and tail, and whitish underparts. Their legs and feet are yellowish-green, changing to a pinkish-red during the breeding season. During the breeding times, they’ll also grow two or three long white plumes on their heads, that will stand up during greeting and courtship displays. Males and females look alike, but the females are a bit smaller in size. The Black-crowned juveniles display a dark grey-brown plumage, with white streaks and spots. Adult plumage is reached by 3-years-old — which is also breeding time.
But my favorite part of these herons are their eyes: a brilliant bright red. And the youngsters? They have an equally gorgeous yellow stare.
Habitat, Diet & Hunting
Black-crowned Night Herons prefer the fresh- and salt-water wetland habitats, including marine islands, swamps, rivers, canals, marshes, mangroves, and the more overgrown edges of lakes and ponds. They remain close to the water and near their favored trees, including pond apple trees, in our area — where they roost and breed.
Their diet consists primarily of fish, but Black-crowned Night Herons will also partake in frogs, insects, crayfish, mussels, squid, reptiles, rodents, and aquatic plants. They’ll also loot the eggs and nestlings of waterbirds, such as terns, herons and ibises, and hunt small birds. Feeding takes place in the shallow waters, where they grasp their prey (instead of stabbing it). It’s a common sight to witness these herons standing stock-still at the water’s edge for long periods of time, waiting for their prey to come into range. They shake their prey until it’s been stunned or killed, at which point the heron swallows it head-first. Yummy!
Black-crowned Night Herons are solitary hunters, and feed in the early morning and at dusk. Theories of their nocturnal habits range from wishing to minimize competition for food with other waders, to avoiding harassment from other birds that are aware of the night herons’ habits of feeding on their eggs and young, and have, therefore, learned to attack night herons on sight.
In the 1960s, Black-crowned Night Herons’ populations suffered a decline that was attributed to the use of DDT. They’re also hunted for food — particularly the juveniles. Additionally these herons are killed at fish farms, where they’re seen as a nuisance. Fortunately, alternate methods for managing many of the associated “issues” with these birds have been implemented, eradicating the need to slaughter these lovely herons.
As with other wading birds, habitat loss and destruction (in addition to water pollution) of their wetland habitats in more recent history have had detrimental impacts in their decreased populations.
SAVE THE WETLANDS and their most lovely and amazing inhabitants!
- If you want to hear a Black-crowned Night heron, listen for a loud and somewhat harsh ‘Qua,’ ‘Quak,’ ‘Quark’, ‘kwark’ or ‘kwok.’
- In many parts of the world, this heron is named for its calls. In the Falkland Islands, it’s referred to as quark; kwak in Dutch and Frisian; and similarly in Czech, Ukrainian, Russian, Vietnamese, Indonesian, and other languages.
- Black-crowned Night Herons can live up to 30 years in captivity, and 20 years in the wild.
- While hunting, these herons use a technique called “bill vibrating.” They open and close their bill rapidly in the water, which creates a disturbance that lures prey.