Night heron Nycticorax nycticorax
Government: wading, family: caperils; subfamily: night blind
In Poland, the species is subject to strict protection, requiring active protection, inscribed in the Polish Red Book of Animals, which defines it as a species of lesser risk, but requiring special attention. In Europe, considered to be a threatened species due to the decline in the population.
In Slavic beliefs, the blind-eyed man played the role of a psychopomposa or guide of souls accompanying the dead on the way across the river separating the world of the living from the dead. Latin name literally means “night crow” and so, as the night equivalent of the crow, it was understood in many cultures. Ślepowron is a mysterious bird – during the day it hides in thick bushes, which it most often leaves after dark. It was night life that decided about the name of the bird. People saw the drowning night heron hidden among the vegetation during the day, they regarded him as “blind”. The second part of the species name comes from the fact that its voice resembles croaking a crow – a throaty “croak”.
What does it look like?
Night heron is a bird smaller than a gray heron with a streamlined body and dimensions from 58 to 65 cm. It has a very distinctive silhouette with the head “pulled in” the torso and quite short legs. Females and males look similar, differ only in body size. In adult birds, the black head is decorated with two or three white, long feathers that reach back halfway. The top of the body is also black, with a green sheen that becomes more intense in the spring robe. The wings and tail are blue-gray, the bottom of the body lighter than them, and the forehead, cheeks and white rump. The black mask covers the red eye, connecting them with the black beak. The legs at the beginning of the breeding period are raspberry-red, for the rest of the year they are yellowish.
The young blind eye differs from the parents, it is dark brown with white flecks on the top of the body and greenish with a dark brown tail on the underside, the eyes are orange-brown, the legs are yellow-green and look like a bittern. In winter, as a result of partial moulting, the whole body of young birds gains a gray-brown color, much darker on the outside. In the second spring robe they resemble an adult bird.
Where raises the young?
Night heron their breeding leads only in several locations throughout the country. The only permanent region of their occurrence is the valley of the upper Vistula, where the majority of the population of this species is concentrated in Poland (the place of breeding and migration). The national population has about 1000 pairs. Night herons mainly inhabit islands, which were selected for carrying out activities in the project, located in four Natura 2000 areas.
They nest colonies, sometimes in the company of other species of herons and gulls, in shrubs growing on islands in water reservoirs or in dense, extensive and hardly available riverside bushes and willow tree plants. Colonies with more than 100 nests are located in places where there are at least 500 ha of feeding grounds within the radius of 5 km (eg freshwater water reservoirs).
How does he live?
The blind-eyed nest is a flat platform made of thin twigs, without padding, about 20-30 cm in diameter. These nests are built in dense thickets, on shrubs, mainly willow and elderberry, at a height of about 3 m above the ground, less often on higher trees. The breeding period of the night blind in colonies, in the valley of the upper Vistula, can be very stretched. In large colonies, the birds arrive even at the beginning of April, and the chicks may be hatching already in May, while in the smaller, new laying eggs takes place only in July. Most of the birds breed for the first time in the third or fourth year of life. An adult female usually proceeds to one brood during the year, during which he makes from 3 to 5 eggs. Incubation lasts 21 – 22 days, and eggs are incubated by both birds from a pair. The chicks are initially unsuspected and have greenish-gray skin. The first feathers are beige and the legs are green-yellow. Young night blinds stay in the nest for about 20 days after hatching. They are fed by both parents for 40-50 days, until they reach their flying abilities.
How does he live?
Ślepowron leads a nocturnal lifestyle. During the day, he rests in hiding on trees and bushes, revives at dusk, then flies to prey. During the breeding season, it is a social species. Apart from him, he lives alone, he feeds one by one, establishing individual hunting territories.
Feeding the night blinds are amphibians, fish and insects that they catch, wade or chat in shallow water. It also eats crustaceans, lizards, small mammals, grass snakes, snails, spiders, leeches and small birds. Young birds are fed with food that is half-digested and returned by adults.
This bird does not overwinter in Poland, but moves to Africa at that time. During the flight period, the night blind is rarely met, but regularly throughout the country, especially in the south. A trip to wintering takes place in a wide front across the Mediterranean Sea and the Sahara. Return to the breeding grounds takes place in March and in April. Birds fly at night, beginning their journey at dusk. Exceptionally, flights were also observed during the day. Ślepowrony fly at a maximum speed of 65 km / h, beating in one episode up to several hundred kilometers. During the day, they rest and feed. During the trip, they make several-week stops to replenish their energy reserves for the further journey. It is assumed that it takes them several months to travel to the Sahel (Central Africa).
- Tworek S., Cierlik G. 2004. Nycticorax nycticorax (L., 1758) – ślepowron. W: Gromadzki M. (red.) Ptaki (część I). Poradniki ochrony siedlisk i gatunków Natura 2000 – podręcznik metodyczny. Ministerstwo Środowiska, Warszawa. T. 7, s. 67-69.
- Bukaciński D., Bukacińska M., Betleja J. 2015. Rybitwa rzeczna Sterna hirundo, Ślepowron Nycticorax nycticorax W: Chylarecki P., Sikora A, Cenian Z., Chodkiewicz T. (red.) Monitoring ptaków lęgowych. Poradnik metodyczny. Wydanie 2. GIOŚ, Warszawa, s.299-305; 354-358.
- Ledwoń M., Betleja J. 2015. Post-breeding migration of Night Herons Nycticorax nycticorax tracked by GPS/GSM transmitters. Journal of Ornithology 156: 313-316.