Night Heron

Black-Crowned Night Heron-Nycticorax nycticorax

Classification

  • Kingdom: Animalia
  • Class: Aves
  • Order: Pelecaniformes
  • Family: Ardeidae
  • Genre: Nycticorax
  • Species: Nycticorax nycticorax

Identification characters

The grey oystercatcher is a medium-sized oystercatcher, averaging 61 cm in body length. It is not sexually dimorphic. The bill is short and the body is stocky. The body is greyish, with a black crown and back. During the breeding season, two longer white feathers are evident on the back of the head. The legs are yellowish-brown and become reddish during the nesting season.

First winter juveniles have brownish-yellowish bodies with small whitish spots. In the second winter, they become adult-like, but are distinguished by a dull, grey-brown crown and back.

Distribution

The Black-Crowned Night Heron has a wide range, mainly covering temperate, subtropical and tropical areas of North and South America, Europe, Africa and Asia. It does not occur in cold areas or in Australia. In Europe the distribution is fragmented, with a relatively small population estimated at 60,000 – 86,100 breeding pairs with a decreasing trend. Winters in tropical Africa.

In Romania, the Nightjar nests in the Danube meadow and Delta, in the floodplains and floodplains of large rivers, but also in other inland wetlands, with larger populations in Muntenia and Moldova.

In Romania the number of breeding pairs is estimated at between 4 000 and 8 000, mostly in the Danube Delta, representing 10% of the European population.

Living environment and biology of the species

The Black-Crowned Night Heronfeeds in areas with lakes, large streams, ponds, shallow vegetated channels, ponds, at the edge of water bodies, in areas rich in marsh vegetation. Nests in trees in wet areas such as meadow forests, willows in reed beds, aspen plantations. In Romania, as in all of southern Europe, the nightjar is a summer guest. At the end of the nesting season it disperses over large areas.

It flies mainly at night or during twilight periods, hence the name given to the species, the nightjar (Nycticorax nycticorax). Both the genus name and the specific epithet come from the Greek words nyx/nyctos – night, respectively korax – raven, referring to the nocturnal activity of the nightjar and its raven-like sounds. During the day it retreats into trees or bushes. They feed solitarily, but can sometimes be seen flying in small groups during the nesting season. Outside the nesting season, nightjars gather in flocks that can comprise hundreds of individuals. Sexual maturity is reached at two years of age.

Food consists mainly of small fish, but they also eat amphibians, leeches, tadpoles and insects. They hunt mainly at dusk, early or late in the day.

Black-Crowned Night Heron return to nesting areas in late March, early April. Rarely, some individuals remain in the Danube and Delta area.

During the nesting period, the Black-Crowned Night Heron is a monogamous species. It nests in monospecific or mixed colonies with cormorants and other species of terns. Nests are built in trees. Adults mate near the nest site from the first days of pair formation. Both parents help build the nest, which is made of twigs and reeds in the shape of a shallow dish. Towards the end of April, the female lays 2-3 blue-green eggs, which are incubated in turn by both parents for 21-22 days. The change to the nest involves a ritual that includes movements to display the plumage. The chicks are fed by both parents until they become independent. At 50-60 days of age, the chicks leave the nest, but remain in close proximity to the nest, waiting for food from the adults. The parents do not always recognise their own chicks, so it happens that they also bring food to chicks from neighbouring nests, especially to those that insistently beg for food.

Threats and conservation measures

The main threat is the burning of reeds, even outside the growing season, as this species establishes colonies in areas with abundant vegetation. Other threats are loss of nesting habitat areas, pollution and poor water management, poaching and other anthropogenic disturbance.

Conservation measures include enforcement of building restrictions in riparian areas, waste management in wetlands, protection of nesting and feeding sites, conservation of forests in the vicinity of aquatic habitats and riparian vegetation, measures to avoid drying and sudden artificial changes in water regime in wetlands. Forestry work to be carried out outside the breeding season. The use of selective and low-toxicity agrochemicals on neighbouring land is encouraged.

It is important to comply with hunting legislation and to monitor its application, through cooperation between environmental protection organisations, hunting organisations, the gendarmerie and the Environmental Guard against poaching.

It is recommended that research be carried out into the impact of the species on commercially exploited resources such as fish species, crustaceans and molluscs in order to match conservation objectives with the activities of the affected sectors.

Last but not least, studies on the inventory of breeding areas, both actual and potential, the identification of migration, feeding and aggregation areas important for the conservation of the species should be encouraged, as well as studies addressing various aspects of the biology of the species, including demographic parameters.

Bibliography

  • Fântână Ciprian, Kovács Istvan, Benkő Zoltán, Daròczi Szilárd, Domșa Cristian, Veres-Szászka Judit (editors), 2022, Atlas of bird species of community interest in Romania, 2nd edition – Love birds, save nature!, Project financed by the European Regional Development Fund through the Large Infrastructure Operational Programme 2014-2020, Ministry of Environment, Water and Forests – Biodiversity Directorate, scientific coordination Romanian Ornithological Society and Association for the Protection of Birds and Nature Milvus Group, produced by EXCLUS PROD SRL, p.112-113;
  • Lars Svensson, Hakan Delin, 1988, Photographic guide to the birds of Britain and Europe, Herons, storks and ibises p. 32, Chancellor Press, London
  • Svensson (text and maps), 2017, Guide to bird identification. Europe and the Mediterranean area, translation and adaptation in Romanian: Romanian Ornithological Society, Emanuel Ștefan Baltag, Sebastian Bugariu, Alida Barbu, p.82;
  • Radu Dimitrie, 1983, Small Ornithological Atlas – Birds of the World, Albatros Publishing, Bucharest, p. 67;
  • https://pasaridinromania.sor.ro/ Ornitodata | Black-Crowned Night Heron (sor.ro)
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