Black-Crowned Night Heron

Black-Crowned Night Heron

Night heron

Kingdom
Phylum
Class
Subclass
Infraclass
Superorder
Family
Genus
SPECIES
Nycticorax nycticorax
Life Span
20-30 yrs
TOP SPEED
55 km/h
WEIGHT
800 g
HEIGHT
63 cm
LENGTH
56-65 cm
WINGSPAN
105-112 cm

The Black-crowned night heron has a stocky appearance, as if hunched over, the head tucked down into the shoulders, and it is usually seen with this posture. Its legs and neck are much shorter than those of other herons. This bird is most active at dusk or at night, their ghostly forms flying from their daytime roosts to the wetlands where they forage. Adults have striking gray-and-black plumage with long white head plumes. These birds breed in colonies, their stick nests usually being built over water. This species lives in a wide range of fresh, salt, or brackish wetlands and they are the world’s most widespread heron.

Distibution

Black-crowned night herons breed on every continent apart from Antarctica and Australasia. In the Americas it is from Washington to Quebec, through coastal Mexico, and in Central America and the Caribbean. In winter they can be found as far north as the New England states and Oregon. The Old World subspecies occurs from Japan to Europe, Africa and India. This heron lives in a wide range of habitats, from swamps, rivers and lakes to salt marshes, lagoons and mudflats. Aquatic and marginal vegetation like mangroves, reed beds, bamboo, and other trees are necessary for nesting and roosting.

Black-Crowned Night Heron habitat map

Geography

Countries
Albania, Algeria, Angola, Antigua and Barbuda, Argentina, Armenia, Austria, Azerbaijan, Bahamas, Bahrain, Show More Bangladesh, Barbados, Belarus, Belgium, Belize, Benin, Bhutan, Bolivia, Bosnia and Herzegovina, Botswana, Brazil, Brunei, Bulgaria, Burkina Faso, Burundi, Cambodia, Cameroon, Canada, Central African Republic, Chad, Chile, China, Colombia, Comoros, Congo, DR Congo, Costa Rica, Cote d'Ivoire, Croatia, Cuba, Cyprus, Czech Republic, Dominica, Dominican Republic, Ecuador, Egypt, El Salvador, Equatorial Guinea, Eritrea, Ethiopia, France, Gabon, Gambia, Georgia, Germany, Ghana, Greece, Grenada, Guadeloupe, Guatemala, Guinea, Guinea-Bissau, Guyana, Honduras, Hong Kong, Hungary, India, Indonesia, Iran, Iraq, Israel, Italy, Jamaica, Japan, Jordan, Kazakhstan, Kenya, South Korea, Kuwait, Laos, Lebanon, Lesotho, Liberia, Macao, Macedonia, Madagascar, Malawi, Malaysia, Mali, Malta, Mauritania, Mexico, Micronesia, Moldova, Montenegro, Morocco, Mozambique, Myanmar, Namibia, Nepal, Netherlands, Nicaragua, Niger, Nigeria, Oman, Pakistan, Palau, Palestine, Panama, Paraguay, Peru, Philippines, Poland, Portugal, Qatar, Romania, Russia, Rwanda, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Saudi Arabia, Senegal, Serbia, Sierra Leone, Singapore, Slovakia, Slovenia, Somalia, South Africa, South Sudan, Spain, Sri Lanka, Sudan, Suriname, Swaziland, Switzerland, Syria, Taiwan, Tajikistan, Tanzania, Thailand, Timor-Leste, Togo, Trinidad and Tobago, Tunisia, Turkey, Turkmenistan, Uganda, Ukraine, United Arab Emirates, United States, Uruguay, Uzbekistan, Venezuela, Viet Nam, Western Sahara, Yemen, Zambia, Zimbabwe, Australia, Cape Verde, Denmark, Djibouti, Faroe Islands, Finland, Iceland, Ireland, North Korea, Kyrgyzstan, Libya, Liechtenstein, Luxembourg, Maldives, Mongolia, Norway, Sao Tomé and Principe, Seychelles, Sweden, United Kingdom, Afghanistan Show Less

Habits and Lifestyle

The Black-crowned night heron is social throughout the year, often associating with other species. In the winter, they roost together. A migrating species, it will fly at night and rest during the day. Its normal call sounds like 'qua,' 'quak,' or 'quark.' Such calls are most often made during flight or when perching. Feeding throughout the night avoids competition with herons that use the same habitat during the day. Feeding sites are repeatedly used. When landing to feed, it alights feet first on water, or plunges out of the air. When it walks, it usually has its head lowered, and it hardly ever runs. On cold days when flying, it may retract its feet to conserve heat. Young leave their perches to huddle in the nest when it is cold. A Black-crowned night heron will defend its feeding and nesting territories. The young may be aggressive, defecating or regurgitating on human intruders.

Diet and Nutrition

Black-crowned night herons are classified as pre-eminently carnivorous, they eat primarily fish and other aquatic life: frogs, tadpoles, snakes, turtles, lizards, the larvae and adult forms of insects, spiders, crustaceans, mollusks, small rodents, bats, chicks and eggs of other bird species.

Mating Habits

MATING BEHAVIOR
REPRODUCTION SEASON
varies with location
INCUBATION PERIOD
21-22 days
INDEPENDENT AGE
6-7 weeks
FEMALE NAME
hen
MALE NAME
cock
BABY NAME
chick
BABY CARRYING
3-5 eggs

Black-crowned night herons seem to be monogamous, one male mating with only one female. Males perform an elaborate courtship display, which is often at night. It walks about in a crouching position, with head lowered, clapping its bill. Next, it flaps its wings, singing and dancing. Once the female accepts, the birds preen each other and touch and clasp each other’s bills. The breeding season varies depending on the range. These birds breed in colonies which may be very big (as many as 5000-6000 pairs in Malaysia). The colonies may include several different species. Nests are made on cliff ledges or in reed beds, tall trees, bushes, or on the ground. 3-5 eggs are laid and two broods per season may be produced. Incubation is for about 21-22 days and both parents brood their young. Chicks leave the nest after two weeks, although they do not go far. By three weeks, they will fly to the tops of trees if disturbed. By 6-7 weeks old they are competent fliers and fly to the feeding grounds. The young are sexually mature at 2-3 years.

Population

Population threats

Although Black-crowned night herons are relatively abundant and widespread, localized threats are a concern for certain populations, in particular, habitat loss, wetland degradation, petroleum and pesticide contamination, hunting and disease.

Population number

According to IUCN’s Red List, the Black-crowned night heron global population size is 510,000-3,600,000, with national population estimates including: 100,000-1 million breeding pairs, over 10,000 individuals migrating and over 10,000 wintering birds in China; in Taiwan 100,000-1 million breeding pairs; in Korea 10,000-100,000 breeding pairs as well as 50-1,000 wintering individuals; and in Japan 10,000-100,000 breeding pairs, with 1,000-10,000 birds migrating. Overall, currently Black-crowned night herons are classified as Least Concern (LC), however, their numbers today are decreasing.

Ecological niche

Black-crowned night herons may have influence on the fish population due to their diet.

Fun Facts for Kids

  • During the breeding season, the night heron male’s legs turn red and feathers at its nape become longer.
  • The Black-crowned night heron is also known as the “quark bird” due to the call it makes when flying through the night.
  • These birds sometimes lure prey by using “bill vibrating”: opening and closing their bills rapidly in water to create a disturbance.
  • These birds have digestive acids that are so strong that bones dissolve in their stomachs.
  • Black-crowned night herons often nest with other bird species such as ibises, egrets and other herons. They will even brood the chicks of other species if these are placed in their nests.

References

1. Black-Crowned Night Heron Wikipedia article - https://en.wikipedia.org/wiki/Black-crowned_night_heron
2. Black-Crowned Night Heron on The IUCN Red List site - http://www.iucnredlist.org/details/22697211/0

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