BLACK-CROWNED NIGHT HERON (Nycticorax nycticorax hoactli) – (See images below)
DESCRIPTION: The Black-crowned Night Heron, as opposed to taller herons, has a stocky body, short legs and a short and large neck. It measures around 24 inches (60 cm) long, and the adult has a black crown and blueish-black back, light grey wings and white under parts including the throat and the neck sides. The bill is large and black, the legs yellow and the eyes are red. Adults have a few long, slender feathers extending from the back of the neck. Sexes are similar, but the male is slightly larger.
NAME: The black-crowned night heron, as the name implies, is ‘supposed’ to be active at night, but as can be seen below, that species is diurnal on Hawaii. The name ‘Heron’ has a complicated origin and evolved from an ancient Greek word meaning ‘to creak or screech’ (in reference to that bird’s call).
A double Latin name means that there is only one species in that genus. The Latin name itself ‘Nycticorax’ is from Greek and means ‘night crow’, because its night call had been confounded with that of a crow.
HABITAT: Black-crowned night herons can be found in different kinds of wetlands – marshes, reservoirs, estuaries, and near bodies of water in cities as well, such as fountains in parks or in front of hotel buildings. In other words, they can be found wherever there are fish, their main diet. Aquaculture farmers consider it as a pest.
DIET: Opportunistic. In addition to fish, black-crowned night herons will also feed on various small animals such as birds, reptiles, amphibians, insects, arthropods and worms. They will eat some plant materials and can be seen at garbage dumps as well. As opposed to other herons who spear their prey, the black-crowned night heron will seize it in its bill and swallow it. There have been observations of some birds actually baiting fish to attract them to the water surface. These herons also prey on the endangered Hawaiian Stilt.
NESTING: As with other heron species, the black-crowned night heron nests in colonies in trees, in an area judged to be sheltered from predators. The colony can include other bird species. The nest is made from small branches and twigs with a flimsy appearance.
DISTRIBUTION: This heron is widespread around the world and one group of the global population breeds in the temperate regions of the northern hemisphere, and migrates not far south of its breeding range. Then there’s another large population of birds which are year-round residents in the southern hemisphere, including Hawaii where they are indigenous.
ON PEI: The black-crowned night heron does not breed (yet) on Prince Edward Island, and its presence is noted as being ‘accidental’ (9 or fewer records per century). One juvenile was observed and photographed at Corran Ban near Grand Tracadie on October 5, 2014 (photo below).
CONSERVATION: the population of the black-crowned night heron has slightly declined over the last few decades but insufficiently to list the bird as being of concern. Some threats include habitat degradation from wetland drainage and water pollution. What helps that bird is that it adapted well to human environments.
REFERENCES: Black-crowned-night-heron – DLNR Hawaii, Oct. 2005 – (New Hampshire PBS)

Black-crowned night heron Ala Moana Park, Oahu - © Denise Motard
Black-crowned night heron
Ala Moana Park, Oahu
Black-crowned night heron at 3:00 pm  Ala Moana Park, Oahu - © Denise Motard
Black-crowned night heron at 3:00 pm
Ala Moana Park, Oahu
Black-crowned night heron juvenile  Grand Tracadie, PEI, Oct. 5, 2014 - by Shawn McCormack
Black-crowned night heron juvenile
Grand Tracadie, PEI, by Shawn McCormack

The video below shows a black-crowned 'night' heron hunting in the Ala Moana canal at 3:00 pm near a fisherman:

This video below shows a black-crowned night heron self-preening at night before going hunting (Ala Moana Park):

The next video shows the same bird as above: