Pucung Kuak (Malay)
Black-crowned Night Herons are small stocky, short-legged compared
to other herons. They are handsomely attired in a tri-colour plumage
of black, grey and white, with two long plumes on the nape.
Night Herons are unpopular with other herons, which attack the Night
Herons on sight. This is because Night Herons are very aggressive
and steal eggs and young of other heron colonies. Perhaps it is
the harassment from other birds that force Night Herons to come
out mainly at night.
Besides fish, Black Crowned Night Herons eat a wide range of prey
from aquatic invertebrates (crustacea, mussels, squid), amphibians
and reptiles (lizards, snakes) to land invertebrates (leeches, earthworms,
insects) including small mammals (rodents). They also eat plants
and are not above eating carrion and rooting around garbage dumps.
Prey is shaken vigorously until stunned or killed and then juggled
about in the beak and swallowed head first. They have strong digestive
acids that can dissolve even bones. Their faeces are white and limey
because of the dissolved calcium.
and wetland wildlife at
Sungei Buloh Nature Park
features: Small (58-65cm, 0.7-1kg): black crown
and back; grey wings and tai; white underparts; eyebrows
and lores whitish; bill black slightly curved downward;
legs and toes yellow (pinkish-red in breeding); eyes red.
Genders look alike.
Juvenile: Very different
in appearance: dark brown overall with wings white spotted;
head white streaks; underparts white spotted or streaked.
Harsh kwark or kwok, in flight or at roost.
But there are many different interpretations of their
In flight: Tucks its neck
close to its body and its short legs barely extends beyond
its tail; white underparts obvious.
Similar birds: Juveniles
look like the juveniles of the
Little Heron (Butorides striatus), Cinnamon
Bittern (Ixobrychus cinnamomeus); these all
lack the Black-crowned's spots on the back, stocky shape
and robust bill.
Status in Singapore: Common
resident throughout the island including North and South
offshore islands (Pulau Ubin and Pulau Tekong).
World distribution: Nearly
world-wide, except Australia and Antarctica. Resident
on the Asian subcontinent, visitors to the Philippines
Classification: Family Ardeidae.
World 65 species, Singapore 17 species.
have surprisingly long necks
other herons, Night Herons hunt in shallow waters using their long
necks and thick bills to snatch at prey.
Slow patient stalkers, they may remain motionless for long periods,
standing with their neck tucked in, giving their typical hunched posture.
Black Crowned Night Herons may also hunt by vibrating their bills
in the water to lure prey into investigating the disturbance. They
may walk about or even swim when searching for food.
Juveniles and adults
out of breeding season may also hunt during the day, possibly because other
herons consider them less of a threat.
breeding bird with red legs
intimidates a non-breeding one
they roost and nest together, and may even travel to feeding sites
in a flock, they usually hunt alone and fiercely defend a feeding
territory from others of their kind.
Although they may fly around during the day, Night Herons hunt throughout
the night and early morning when the other herons are sleeping. But
when food is scarce or in high demand (e.g., during the breeding season),
they may also hunt during the day.
Black Crowned Night Herons prefer to nest and roost in mangroves, but prefer
to hunt in freshwater wetlands. They travel to and from these hunting sites
in long skeins in the evening, returning at dawn. They are found wherever
there are suitable trees for roosting and nesting. Usually near brackish
and freshwater wetlands: mangroves, mudflats, estuaries, ponds, reservoirs,
canals, rivers. But they have also been observed in suburbs of large cities.
Breeding: Black Crowned Night Herons
appear to breed year-round. In Singapore, they used to nest in Khatib Bongsu
before fogging chased them off. One colony of about 20 pairs survive at
the Jurong Lake area. Elsewhere, they have been known to roost in huge breeding
colonies containing tens of thousands of birds.
During breeding season, their head plumes become longer, their black plumage
take on a bluish-green gloss and their legs, feet and lores turn red. Believed
to be monogamous, the males perform an elaborate courtship ritual, usually
at night. They clapper their bills as they walk in a crouch, followed by
wing flapping and a song and a dance (hissing as they rock from foot to
foot). At first, the female may be rejected, but eventually she is accepted
and they preen each other. During courtship, the male also presents sticks
to his chosen female. When the pair bond is formed, their legs blush a pinkish-red!
young fledge in about 2-3 weeks but don't leave their parents until about
6-7 weeks. They can live for about 20 years in the wild and 30 years in
Crowned Night Herons nest in colonies, sometimes with other colonies
of herons. In the Malay-Thai peninsula, they prefer to nest in mangroves,
especially in the Avicennia
spp. Elsewhere, they may nest in coconut palms, bushes, reeds
as well as at ground level on grassy tussocks. The nest is a made
of sticks, twigs and reeds, lined with softer materials like roots
and grass. The first nest built by young birds are fragile, but as
they re-use the nest over the years, it become a bulky platform. Large
colonies in mangrove trees, however, can kill the nest trees by heavy
coatings of their dropping, forcing them to relocate regularly. The
male usually begins the nest building by repairing an old one or starting
a new one. Eventually, the pair divide the work between them, the
male gathering the sticks and the female doing most of the constructing.
3-6, average 3, pale blue-green eggs are laid. Both parents incubate.
On hot days, they may cool off the eggs by wetting their feathers.
In 24-26 days, nearly naked hatchlings emerge. Both parents raise
the young on regurgitated food at first, then whole prey as they young
are older. The young usually scramble out of the nest and wait nearby
for their parents to return. They are aggressive and will throw up
on intruders. As a last resort, they may throw themselves into the
water and paddle away. When parents return to the nest, they signal
to the young so they know they are not predators, by bowing to show
their glossy black crown and long white head plumes.
estimate the age of a young bird by its coloration.
they are a year old, they look very different from the adults;
dark brown with white streaks and spots.
When they are 2 years old, the crown and back are brownish-black;
rest of body brown; underparts with faint streaking. They get
their adult colouring at age 3 years when they reach breeding
adults have bright red eyes, juveniles first have grey eyes
which turn yellow then red.
Migration: Most Black Crowned Night Heron populations in our
region are resident. A few populations that breed in the north may migrate,
doing so at night and resting during the day. During their migration, they
call to keep together.
Status and threats: Although Black Crowned
Night Herons are among the most common herons in the world, this bird is
on the Red Data list of Singapore. It is threatened by habitat loss; its
preferred habitat are considered mosquito breeding sites and are not tolerated
near human homes or regularly fogged. One traditional breeding site in Singapore
was at Khatib Bongsu where up to 1,200 birds nested. This colony was destroyed
by fogging which poisoned the birds. The birds have not returned. The birds'
popularity is not aided by the fact that they are also a carrier of Japanese
Encephalitis, a dangerous disease. In other parts of the world, they have
been hunted for food (they apparently taste good, especially the young birds)
or as a pest at fish farms. Like other wetland inhabitants, they are also
threatened by water pollution and the overuse of pesticides.
Diversity Webpage on the University of Michigan website by Alicia
Ivory: fact sheet on distribution, habits (breeding, feeding), habitats,
conservation, photo and links.
Community College, University of Hawaii by Vivian Villanueva: lots
of details on breeding and other habits.
of Nova Scotia: fact sheet on breeding, habits and description,
in and around the Hamilton Harbour Area on the McMaster University
website: fact sheet.
Wildlife Research Centre: description of difference with photos
of adult and juvenile.
Guide to the Birds of Kern County: fact sheet.
Parks and Wildlife: fact sheet.
Prairie Wildlife Research: fact sheet.
zoo: fact sheet.
Street Boat Basin Flora and Fauna Society: article by by Leslie
Day: fact sheet. photo.
Vertebrates of Singapore on the Singapore Science Centre website:
Brief fact sheet, photo.
British Birds (1826) on the Brontes website: Vol. 2: The Night Heron:
brief fact sheet, engraving.
- A replica of
the complete John
James Audubon's Birds of America (1840-1844) On a website by creative
multimedia corp: fact sheet with full text, color plates, figures and
Zoo (Washington DC): detailed fact sheet.
- Morten Strange,
"A Photographic Guide to Birds of Malaysia and Singapore: including
Southeast Asia, the Philippines and Borneo", Periplus, 2000
(p. 53: description, voice, habits, distribution, status, photo).
- David R Wells,
"The Birds of the Thai-Malay Peninsula: Vol. 1 (Non-Passarines)",
Academic Press, 1999 (p. 91-93: identification, distribution map, habits,
habitat, migration, conservation).
- Lim Kim Seng,
"Pocket Checklist of the Birds of the Republic of Singapore",
Nature Society (Singapore), 1999 (Abundance, status, Chinese and Malay
- Lim Kim Seng and
Dana Gardner, "Birds: An Illustrated Field Guide to the Birds
of Singapore", Sun Tree Publishing Ltd., 1997 (p. 85: identification,
status in Singapore, distribution, diagram, number of species)
- G W H Davison
and Chew Yen Fook, "A Photographic Guide to Birds of Peninsular
Malaysia and Singapore", New Holland Publishers Ltd., 1995
(p. 19: identification, status in Singapore, distribution, photo).
- Morten Strange
and Allen Jeyarajasingam, "Birds: A Photographic Guide to the
Birds of Peninsular Malaysia and Singapore", Sun Tree Publishing,
1993 (p.112: description, distribution, habits, habitat, photo).
- Clive Briffett,
"A Guide to the Common Birds of Singapore", BP Science
Centre,1992 (p. 47: habit, habitat, breeding site in Singapore)
- P K L Ng and Y
C Wee (ed.), "The Singapore Red Data Book", The Nature
Society, 1994 (p.230: habits, habitat, distribution and breeding site
- Peter K L Ng (ed.),
"A Guide to the Threatened Animals of Singapore", BP
Science Centre, 1995 (p. 128: photo, habitat, threats)
- Christopher Hails,
"Birds of Singapore" illustrated by Frank Jarvis, Times
Editions, 1987 reprinted 1995 (p. 56: habits, description, status in
Singapore, and lovely drawings of the birds).
- Lim Kim Seng,
"Vanishing Birds of Singapore", Nature Society (Singapore),
1992 (p. 20-21: distribution and status in Singapore and details of
the effect of fogging on the breeding site at Khatib Bongsu; fact sheet
on all aspects).
- James Hancock,
"Herons and Egrets of the World: A photographic journey",
Academic Press, 1999 (p. 168-170: identification, distribution, status,
feeding, breeding, and photos of all life stages)
- John Palmer (ed.),
"Exploring the Secrets of Nature", Reader's Digest,
1994 (p. 55: parents identifying themselves to chicks).