Average white egret. Enemies, unfavorable factors
Class - Birds / Subclass - New palates / Superorder - Cioriformes
History of the study
Middle egret (lat. Egretta intermedia) is a species of bird in the heron family.
Spreading
Mainly found from eastern Africa along tropical zone south asia and to Australia.
Appearance
Medium sized heron.
As a rule, males are several larger than females. The plumage is completely white. The beak is long, straight, colored yellow. The paws and toes are long and dark gray. The neck is long, S-shaped.
Reproduction
Typically nests in colonies with other herons, often on platforms made from piles of tree branches and bushes. The female lays 2-5 eggs.
Lifestyle
Herons inhabit the coasts and shallow waters of fresh and brackish water bodies. On Shikotan Island, the birds nested in a swampy creek valley overgrown with reeds and Kuril bamboo with isolated groups of trees. Spring migrations are in April - May, autumn migrations are in September. The nest, found on the island of Shikotan, was located in the fork of a willow trunk, 5 m from the ground. Construction material: willow branches, Kuril bamboo stems and dry grass. There were 2 chicks in the nest on July 12 and 13. The lifestyle has not been studied. The main food is fish and aquatic insects.
Nutrition
It looks for food in flooded fields and feeds by slowly wandering in shallow water. Sometimes it looks for prey from the branches of low trees. It feeds on frogs, crustaceans and insects.
Number
At a low level. One pair of birds nested on Shikotan. On Sakhalin, during the period of migrations and summer migrations, solitary birds were most often observed.
Great Egret and Man
Hunting of herons is prohibited. It is important to preserve wetlands, eliminate disturbance, limit the number of crows in the nesting areas of this species, and protect birds at nesting sites.
Class: BIRDS (AVES)
Squad:STORKIFORMES (CICONIIFORMES)
Family: HERONS (ARDEIDAE)
View:GREAT WHITE EGRET, EGRETTA ALBA (LINNAEUS, 1758)
WHITE CHAPEL
Description:
A large heron with a very long, thin and steeply curved neck, long legs and a relatively short body (average body length 85-102 cm, weight 1.1-1.5 kg). The wingspan is 140-170 cm. The plumage is snow-white. During the nesting period, there are elongated ruffled feathers (aigrettes) on the back, extending somewhat beyond the tail. It is one and a half to two times larger than the little egret; unlike it, it has black fingers and, in non-breeding times, a yellow beak.
Distribution:
The nominative subspecies lives in Belarus, the dispersed breeding range of which covers the southern and central parts of Europe to Central Asia, south to Iran. Largest part populations are concentrated in southern Russia, Ukraine, and partly in Hungary, Austria and Romania. The northernmost nesting sites have been known since the 1970s and 80s in Latvia and Holland. In Belarus it nests in the south in several local settlements. IN recent years flights have become more frequent throughout the republic, right up to the Vitebsk region. in the north, especially at the end of the breeding season - in August-September. The main wintering grounds of European populations are located in northern Africa, Central Asia, as well as in its southwestern and southern parts.
Habitats:
It nests along the banks of reservoirs (including artificial ones), densely overgrown with shrubs and coastal herbaceous vegetation, in island forests among bushy and swampy river floodplains. When feeding and during migration, it is also found in the cultivated landscape, in shallow waters and coastal spits of lakes, rivers, and fish ponds.
Biology:
nesting migratory species. Arrives at the end of March-April. It nests both in monospecific colonies and together with other herons and great cormorants, less often in separate pairs. It makes nests made of dry reeds or twigs on reed creases or bushes. In the nest there are from 2 to 6 (usually 4-5) oblong, bluish-greenish eggs. Average dimensions 62.7 × 41.7 mm. Incubation, which lasts 25-26 days, begins in the second half of April. After breeding is completed, starting in July, young birds disperse widely (up to 400 km) in all directions. It feeds mainly on fish and aquatic insects.
Number and trend of its change:
From the end of the 19th to the mid-20th century, there was a gradual but steady decline in the number of the species throughout almost the entire European range. At this time, isolated flights of herons to the south of Belarus were noted. After 1965, a reverse process of increasing numbers and expanding the range was observed. Since the 1980s, bird sightings have become more frequent in Belarus, located at the northern limits of the main breeding range. By the beginning of the 1990s, nesting was known from brief descriptions of three cases of finds of single nests or chicks of herons in the Petrikovsky, Luninets and Zhitkovichi districts. Subsequently, starting from 1993, single nests and colonial (from 5 to 40 nests) settlements of great white heron were discovered in Khoiniki, Luninets, Drogichin, Pinsk, Berezovsky, Malorita, Zhitkovichi districts. Judging by the increasing number of bird registrations throughout Belarus and the emergence of new colonies, since the late 1980s there has been an increase in the number of species, probably both due to expansion from adjacent territories and due to the growth of the Belarusian bird population. Long-term forecast is difficult due to significant interannual fluctuations in abundance characteristic of the species population as a whole. The total number is estimated at 50-250 breeding pairs.
International relevance:
The species is included in Appendix I of the EU Conservation Directive rare birds, Annex II of the Berne Convention, Annex II of the Bonn Convention.
Main threat factors:
Reduction in area and degradation (drainage, overgrowth, deforestation of floodplain island forests) of natural swampy floodplains. Disturbance at nesting sites.
Security measures:
The species has been listed in the Red Book of the Republic of Belarus since 1981. Conservation of natural floodplain ecosystems of the river. Pripyat. Monitoring and protection of known nesting sites, as well as timely identification and protection of new habitats. Application and encouragement of traditional, without the use of mechanization, methods of haymaking in the floodplain areas of the river. Pripyat to prevent overgrowing (budding) of the floodplain. Reducing the disturbance factor in the area of the colonies during the nesting period.
Middle Egret- Egretta intermedia see also 5.2.2. Genus White herons Egretta Average egret Egretta intermedia Similar to the great egret, but smaller (wingspan up to a meter), and with a shorter beak (shorter than middle finger). Ring around the eye... Birds of Russia. Directory
average egret- vidutinis baltasis garnys statusas T sritis zoologija | vardynas atitikmenys: lot. Casmerodius intermedius; Egretta intermedia English. intermediate egret vok. Mittelreiher, m rus. white egret, f pranc. aigrette intermédiaire, fryšiai:… … Paukščių pavadinimų žodynas
Little egret- Egretta Egretta see also 5.2.2. Genus White herons Egretta Little egret Egretta garzetta. Similar to a great white heron, but almost twice as small (wingspan 60-90 cm). The beak is black, in winter and in young birds the mandible is yellow, the ring... ... Birds of Russia. Directory
Heron- ? Herons Gray Heron Ardea cinerea Scientific classification Kingdom: Animals Type ... Wikipedia
EGYPTIAN HERON- (Bubulcus ibis), a species of long-legged birds of the genus Small Chepur of the family of heron birds (see HERONS); medium-sized bird: body length 48-53 cm, wingspan 90-96 cm, wing length 22-25 cm. Weight 300-400 g. Plumage color white, mating season upper... Encyclopedic Dictionary
Herons- Pain... Wikipedia
Egrets- White herons ... Wikipedia
General characteristics and field characteristics
A slender heron of medium size (body length about 70 cm) and a typical “heron” build. The plumage is loose, pure white. In the breeding plumage on the back there are long ruffled feathers (aigrettes), protruding 10-15 cm beyond the top of the tail. On the underside of the neck and craw there are ruffled feathers up to 20 cm long, forming a “mane”. There are no elongated feathers on the head. Seasonal changes in beak color are characteristic.
Larger in size than the little and yellow-billed egrets, but smaller than the southern and great egrets. In terms of flight and the nature of movement on the ground, it also occupies an intermediate position between the relatively small (small, yellow-billed) and large (great and southern) white herons. In addition, it differs from the yellow-billed and little egrets by the toes of the same color with the tarsus (black, not yellow), and in breeding plumage by the absence of elongated feathers on the back of the head and relatively longer aigrettes, extending far beyond the top of the tail. In addition to its smaller size, it differs from the southern and great egrets by its entirely black legs, high at the base and shortened beak, and in breeding plumage by the presence of long feathers on the crop. On close range It is noticeable that in the average white heron the corner of the mouth ends just below the eye, and does not extend much further, as in the great white (Cramp, 1977; Beaman and Madge, 1998).
The flight is calm and straightforward, with deep flapping of the wide wings. Takes off easily and quickly. During flight, the legs are extended beyond the top of the tail, and the neck is bent in a vertical plane and pulled into the shoulders. Inhabits wetlands. Lives together with other species of herons. During the period of migrations and migrations, it prefers to stay in groups, often teaming up with other species of white herons, forming sparse clusters when feeding. Immature birds in summer period lead a nomadic lifestyle, occurring far beyond the breeding range.
Description
Coloring. There is no sexual dimorphism in coloration; however, males have slightly longer decorative feathers than females.
Adult male and female. The plumage is white. Legs entirely black; the bare skin of the “face” is yellowish-green during the nesting period, and yellow the rest of the time. The iris is pale yellow. In breeding plumage the beak is black with a yellow base, the rest of the time it is yellow with a black tip. During the mating season, there are decorative feathers on the crop and back (aigrettes).
First down outfit. The fluff is white. The beak is flesh-pink with a black tip.
Second down outfit. The fluff is white. The beak is yellowish with a black tip.
Nesting outfit. The plumage is white. The beak is yellow with a black tip. The bare skin at the corners of the beak, on the frenulum and around the eye is yellowish. Legs are blackish.
First annual outfit. The plumage is white. There are no decorative feathers on the back and lower part of the neck. The beak is yellow with a dark tip. The bare skin on the frenulum and around the eye is yellowish. Legs are black.
Structure and dimensions
Slender bird. The neck is long and thin, but looks noticeably thicker and shorter than those of other egrets, and the legs are long. The beak is relatively somewhat shorter and higher than that of other egrets found within Russia.
Dimensions (mm). The length of the wing of males is 290-325, tarsus 110-130, beak 70-96 (Stepanyan, 2003). The bird caught in Primorye (sex not established) had a wing length of 307, a tarsus length of 101, and a beak length of 96 (Buturlin and Dementyev, 1935). Sizes of males and females from China: wing length 280-330, tarsus length 98-100, beak length 67.5-100 (Ivanov, 1961). Individuals from the North. Koreas: female - wing 313, tarsus 114, tail 122, beak 74; bird of indeterminate sex - wing 308, tarsus 111, tail 118, beak 71 (Tomek, 1999). Birds caught on Sakhalin: males (n = 2) - wing 303 and 313, tarsus 117-118, beak 76 and 76.5 (Takahashi, 1937); female - wing 290, tarsus 105, tail 123, beak 71 (Nechaev, 1991).
Birds caught in the Primorsky Territory: males (n = 2) - wing length 300 and 300, tarsus length 105 and 115, beak length 75 and 75; females (n = 3) - wing length 295, 300 and 300, tarsus length 100, 103 and 105, beak length 70, 74 and 75; birds whose sex is not established (n = 3) - wing length 290, 295 and 300, tarsus length 103, 108 and 110, beak length 70,71 and 72 (col. BPI FEB RAS and FESU, Vladivostok).
Sizes of males and females (mm) of subspecies E. i. intermedia (Cramp, 1977): wing length on average 299 mm (275-327, n = 13), tail length - 118 (103-135, n = 7), beak length - 72.8 (66-76, n = 14), tarsus length - 106 (93-111, n = 7).
Weight of birds from China: males (n = 2) - 470 g and 642 g, female - 600 g, bird whose sex is not established - 700 g (Ivanov, 1961). Female caught in the South. Sakhalin, weighed 458 g (Nechaev, 1991).
Shedding
The full annual molt of adult birds occurs from July to November. Partial prenuptial molting occurs during wintering grounds. Young birds in nesting plumage begin changing small feathers in August, continue in the fall and finish during wintering; in the second year of life they undergo a full annual molt.
Two birds caught in the area of the hall. Olga (Primorsky Territory) on May 20, 1980, were in breeding plumage, however, the male’s beak was yellow with a dark top, and the female’s was black with a yellow base. Of the three birds caught on the lake. Khanka, one individual dated June 30, 1978 had no signs of molting; in specimen from July 15, 1977, the molting of small plumage began; an adult female captured on July 25, 1980 was in the midst of a complete moult (about a third of the flight and tail feathers were lost or growing, and intensive molting of small plumage was occurring).
Subspecies taxonomy
A polytypic species, the geographical variability of which is manifested in general sizes and varying the color of unfeathered parts of the body (beak, legs, bridle). Three subspecies, of which only the nominative is known within Russia.
1.Egretta intermedia intermedia.
Ardea intermedia Wagler, 1829, Isis, stb. 659, Java.
The overall size is somewhat larger, and the color of the unfeathered part of the lower leg is black, and not yellowish-orange, as in the other two subspecies. During the non-breeding season, the beak is yellow with a black tip. Inhabits the South, South-East. and, partly, Vost. Asia.
Subspecies E. and plumifera (Gould, 1848) (2) is common in Australia, on the island. New Guinea and the adjacent islands, has smaller sizes, and in terms of the color of the unfeathered parts of the body it is close to the African race. Subspecies E. and brachyrhyncha (A.E. Brehm, 1854) (3) distributed in the Center and South. Africa, is close in size to the nominate subspecies, but has a yellowish-orange beak and an unfeathered part of the tarsus.
Notes on taxonomy
The great egret is sometimes placed in the monotypic genus Mesophoyx Sharpe, 1894 (more often treated as a subgenus of the genus Egretta) or placed in the genus Casmerodius Gloger, 1842, along with the great egret. DNA hybridization studies have shown that the great egret and egret are more closely related to the genus Ardea than to Egretta (Sheldon, 1987). Thus, systematic position the average egret requires further study and clarification.
Spreading
Nesting area. Center, and South. Africa, Sri Lanka, Burma, Indonesia, China, Japan, Korean Peninsula, Maluku Islands, North. and Vost. Australia (Spangenberg, 1951; Stepanyan, 2003; Vaurie, 1965; Dickinson, 2003; etc.). Great egrets of the nominate subspecies breed in the central and southern regions of China, on the islands of Taiwan and Hainan (Mackinnon, Phillipps, 2000), in Hong Kong (Carey et al., 2001), in the central and southern regions of the Korean Peninsula (Won Pyong-oh, 1996; Tomek, 1999), in Japan - on the islands of Honshu, Shikoku, Kyushu and Sado (Check-list of Japanese birds, 2000), as well as in India and Sri Lanka (Fig. 59).
Figure 59.
a - nesting area, b - established isolated nesting sites, c - wintering areas of northern populations. Subspecies: 1 - Egretta i. intermedia, 2 - E. i. plumifera, 3 - E. i. brachyrhyncha.
In the south Far East In Russia, nesting has been registered on the lake. Khanka (Polivanova, Glushchenko, 1977; Glushchenko, Mrikot, 2000) and on the island. Shikotan, Kuril Islands (Dinets, 1996). A nesting attempt was observed in the area of Olga Bay, Primorsky Krai (Labzyuk, 1981). In addition, nesting is expected in the extreme southwest of Primorye (Litvinenko, Shibaev, 1999) (Fig. 60).
Figure 60.
a - established nesting site, b - area where birds meet during seasonal migrations and summer migrations, c - proposed nesting site, d - migrations.
Wintering
Birds of the nominate subspecies winter in the South-East. Asia: in the southern regions of China, on the islands of Taiwan and Hainan (Cheng Tso-Hsin, 1987; Mackinnon, Phillipps, 2000), the Philippines, Kalimantan, Indonesia (Vaurie, 1965), Vietnam (Vo Qui, 1983), Thailand (Lekagul, Round, 1991), in the southern regions of Japan (Kyushu Island and islands located to the south) (Check-ist of Japanese birds, 2000), Hong Kong (Carey et al., 2001).
The first flights into the territory of the Primorsky Territory were recorded at the beginning of the 20th century (Buturlin, Dementyev, 1935; Belopolsky, 1955). Since the 1960s. they became more frequent and regular (Litvinenko, Shibaev, 1965; Labzyuk et al., 1971; Elsukov, 1974; Glushchenko, 1981; Labzyuk, 1981, 1990). Flights have been recorded in the Lower Amur region (Babenko, 2000), on Sakhalin (Nechaev, 19916), Moneron (Nechaev, 1975), South. Kuril Islands: Kunashir (Nechaev, 1969) and Shikotan (Dykhan, 1990) and Kamchatka (Artyukhin et al., 2000). In the northern part of Japan, flights to the island have been recorded. Hokkaido (Check-list of Japanese birds, 2000).
Migrations
In South Primorye spring migrations take place at the end of April and in May. The earliest appearance was recorded on April 14, 1993 in the extreme south of Primorye at the mouth of the river. Tumanaya (data from Yu. N. Glushchenko), April 26, 2004 in the vicinity of Ussuriysk (Glushchenko et al., 2006), April 27, 1994 on lake. Khanka (Glushchenko et al., 2006) and April 27, 1979 in the hall. Olga (Labzyuk, 1981). Post-nesting migrations on the lake. Khanka occur in August, and the latest reliable meeting in the fall was noted on September 17, 1973. In the vicinity of Vladivostok (the mouth of the Shmitovka River), one individual was observed on September 16, 2007 (data from Yu. N. Glushchenko). On about. Shikotan two birds were observed on October 16, 1986 (Dykhan, 1990).
Habitat
On Khanka, two colonies in which white herons nested were located in the estuary part of the river. Muddy in a strip of flooded willows surrounded by lake-marsh massif. The feeding areas here are damp meadows, grass swamps, shallow lakes and rice fields. On about. Shikotan birds nested in the swampy floodplain of the stream, in reed thickets with clumps of Kuril bamboo and groups of trees (Dinets, 1996). During the period of seasonal migrations and summer migrations, white herons are found along the banks of lakes, rivers and reservoirs, in rice fields, wet meadows and grassy swamps, both inland and on the coast.
In China, the Korean Peninsula and Japan, egrets inhabit grassy swamps, wet meadows, marshes, mudflats and rice fields (A field guide to the birds of Asia,
1993). In Japan, they make nests in pine trees and bamboo thickets (Jahn, 1942), on the Korean Peninsula - in trees surrounding rice fields (Gore, Won Pyong-oh, 1971).
Number
On the lake Khanka nests irregularly and with variable numbers. For the first time, two nests were discovered in the estuary part of the river. Muddy in 1971 (Polivanova, Glushchenko, 1977). In 1973-1980 the species was recorded almost annually in the summer in the southern and eastern regions Prikhankai lowland, and in 1976-1977. noted young individuals, which suggests their irregular nesting in this period(Glushchenko, 1981). In 1999-2002 Great egrets were again found nesting in the same colony, but their numbers, determined in 1999 and 2000, were respectively, 20-30 and 30-40 breeding pairs (Glushchenko, Mrikot, 2000), turned out to be overestimated. In reality, from 7 to 10 pairs could nest here (Glushchenko et al., 2003). In 2000, 8 pairs nested, and three nests inspected contained 1, 3 and 4 eggs. In 2002, the species was not found here at all, and in June 2003, from 1 to 3 birds were observed in one of the subcolonies of the river delta. Muddy. Single individuals were also seen feeding in the meadows in the vicinity of the village. Sivakovka (Glushchenko et al., 2003).
On the coast hall. Olga (Primorsky Territory) at the mouth of the river. In Avvakumovka, an unsuccessful nesting attempt was noted: the birds began to build a nest, but later it turned out to be abandoned (Labzyuk, 1981). In addition to the breeding population, in the southern and eastern regions of Primorsky Krai in the warm season (mainly from May to July), individual single birds and their groups of up to 10 or more birds were regularly seen (Litvinenko, Shibaev, 1965, 1999; Labzyuk et al., 1971; Elsukov, 1974; Voloshina et al., 1999; Labzyuk, 1981, 1990; On about. In Shikotan in 1988, a nest with two chicks was found (Dinets, 1996).
In Japan, the common egret is sparse in summer and sparse in winter in the extreme south (A field guide to the birds of Japan, 1982). In China it is a common species (Mackinnon and Phillipps, 2000); in Hong Kong - common in both summer and winter (Carey et al., 2001); in North Korea - rare for nesting (Toshek, 1999), and in South. Korea - not numerous during the nesting season (Won Pyong-oh, 1996).
Reproduction
Daily activity, behavior
Leads daytime look life. Herons usually feed alone, but sometimes they can gather in flocks of tens or even hundreds of birds (Martinez-Vilalta, Mods, 1992). The behavior of the species on the territory of Russia has not been studied.
Nutrition
The main food items are aquatic and terrestrial invertebrates (mollusks, spiders, insects and their larvae) and vertebrates (fish, amphibians). The stomach of a bird caught on the island. Sakhalin on May 26, 1974, contained the remains of larvae of aquatic insects (Nechaev, 1991). In the stomach of a bird caught on June 30, 1978 at the lake. Khanka, turned out to be a sleeper firebrand (Perccottus glenii) and three dragonfly larvae, and in the stomach of an individual caught there on July 25, 1980, three swimming beetle larvae, a spider and the remains of insect chitin were found (Glushchenko, orig.).
Enemies, unfavorable factors
In a colony on the coast of the lake. Khanka herons experience powerful pressure from their main competitor - the great cormorant. Other significant negative factor Here - high level disturbances from people and livestock. It is especially large in dry years, when the swampy lowland becomes easily accessible (Gusakov, Vinogradov, 1998). Catastrophic consequences for those nesting on the lake. Hanging of birds may involve the destruction of willow thickets by fires at the location of the colony during dry weather (Glushchenko, 2005).
In Japan, the common egret was abundant in the past, but habitat pollution and disturbance of birds in colonies led to significant declines in numbers starting in the 1960s. (Martinez-Vilalta, Motis, 1992).
Economic importance, protection
How very rare species economic importance does not have. Listed in the Red Book Russian Federation(2001) and the Red Data Book of the Primorsky Territory (2005). Location of the colony on the lake. Khanka is part of the Khankaisky protection zone state reserve. It is recommended to increase the area of this reserve by including the territory of the specified colony in its composition.
The great white egret is one of the large birds of the heron family, distributed in warm, temperate and tropical latitudes of the western and eastern hemispheres.
Taxonomy
Latin name- Egretta alba
English name
- Great egret, great white heron
Class- Birds (Aves)
Squad- Storks (Ciconiiformes)
Family- Herons (Ardeidae)
Genus- White Heron (Egretta)
Conservation status
The great egret is included in the International Red List of Species of Least Concern.
In the 19th and early 20th centuries, the world population of great egrets declined by almost 95%, but then recovered almost everywhere. For example, the Astrakhan Nature Reserve was created in Russia in 1919, mainly to protect the great egret. Now total number Great white herons in Europe are estimated at 11–24 thousand pairs, of which in the European part of Russia - 5–7 thousand pairs.
Species and man
In the 19th century, the population of the great white heron was undermined to a large extent due to hunting for this beautiful bird. Special feathers on the back that appear during the mating season - aigrette - were used to decorate ladies' hats. For this reason, herons were destroyed in huge numbers, and on the territory of both hemispheres. So, in 1898 alone, more than 1.5 million herons were killed in Venezuela for the sake of aigrette. From one bird you can get only 30–50 aigrettes, but to get 1 kg of these feathers, you had to kill 150 birds. To save endangered birds, and great white herons in the first place, the famous Royal Society Bird Conservancy (UK), which is now Europe's largest conservation organization.
Currently, great egrets are not hunted anywhere. Thus, direct anthropogenic impact is excluded, but indirect impact has become more significant - loss of habitat and its pollution with heavy metals and pesticides. These substances negatively affect the health and fertility of birds (high levels are noted both in the tissues of adult birds and in eggs).
Distribution and habitats
The great egret is distributed in temperate, warm and tropical latitudes of Europe, Asia, Northern and South America, Africa, Australia and New Zealand. Lives on the sea coast, on inland salt and fresh lakes, along river banks, in mangroves. It is also found in agricultural lands, in fields, especially wet rice fields, along drainage ditches.Appearance
great egret large bird about 1 m high and wingspan 130–140 cm; The weight of adult birds is about 1 kg. As a rule, males are larger than females; There are no other signs of sexual dimorphism. The plumage is completely white. During the mating season, long openwork feathers grow on the back - aigrette, which the birds actively display. The beak is long, straight, yellow. The legs and toes are long and dark gray. The neck is long, s-shaped. Sixth cervical vertebra has special structure, thanks to which the heron can quickly extend its neck and retract it back.
Lifestyle and social behavior
Great white herons living in temperate latitudes are migratory; they winter in Africa and tropical Asia. Most southern heron populations are sedentary or have small migrations.
Great white herons walk slowly and majestically on the ground, looking for prey. Their vision is binocular. The flight is smooth, its speed is 30–50 km/h. When flying, it moves its head back, bending its neck in an s-shape.
They hunt alone or in small groups during the day or at dusk, and at nightfall they seek shelter, forming large flocks, often with other species of herons. They behave quite aggressively, often getting into fights for prey with other birds, including those of their own species.
After the end of the nesting season, young herons fly away from their native nest, sometimes at a distance of up to 400 km.
Vocalization
Nutrition and feeding behavior
The great white egret is a true predator. Its diet includes fish, frogs and their tadpoles, small rodents, birds and their chicks, crustaceans, various insects. Herons are not picky when choosing food, but the main food is still fish.
During the breeding season, they prefer to look for food near the nest, but can fly up to 20 km. The feeding activity of herons is purely diurnal. Adult birds begin to fly for food at dawn, and the greatest activity occurs from 3 to 8–9 am, and then weakens during the day. The second peak of activity, smaller than the morning one, is observed from 15–16 hours to 19–20 hours. Great white herons strictly guard their feeding area and often get into fights with birds of other species. However, if there is a lot of food, they can hunt in small flocks.
When hunting, the great egret often stands motionless on one leg, looking for prey in the water. If the water is high, the bird stands on the shore with its head tilted towards the water. Having discovered prey, the heron makes a swift lunge with its neck and snatches the victim with its sharp beak. Sometimes birds wander slowly (or quickly) through shallow water, but many ornithologists believe that by standing in one place, a heron can catch much more food. It swallows caught prey whole.
Reproduction, rearing of offspring and parental behavior
The great egret is monogamous, but pairs are formed, as a rule, for one season, although there are known cases of some pairs reuniting during next year. It nests in large colonies with other heron species, often smaller ones. In temperate latitudes, nesting occurs in warm time year (spring and summer), in the tropics - all year round.
The courtship ritual of these herons, during which even the appearance birds, quite complex. During the breeding season, birds of both sexes change the color of their beaks and non-feathered parts on the head, and the famous aigrette grows strongly. Usually the males are the first to arrive in the colony and choose places for future nests. Priority here belongs to older males, they choose best places closer to the center of the colony. Having chosen a place and secured it for himself, the male begins a ritual dance, attracting the female. Females sit on neighboring trees and carefully watch what is happening. Sometimes they do a reciprocal dance, sometimes even small fights occur between them. Herons choose partners very pickily, and sometimes one bird can drive away another, for some reason it doesn’t like it.
The heron begins to build a nest as soon as a pair has formed.
Nests are placed on tall trees(not lower than 10 m), growing near water; less often - on bushes (in the absence of suitable trees). The nest is a rather untidy pile of branches different sizes, folded in one place. The male usually collects material for the nest, often simply stealing it from neighbors, and the female lays it down. The diameter of the nest is 60–80 cm, its height is 50–60 cm. Sometimes the nest can be used the next year, unless the herons change the location of the entire colony. Despite colonial nesting, the male very actively defends his site and nest, screams loudly and attacks the stranger.
The female lays 3–6 bluish-green eggs at intervals of 2–3 days. Usually there is one clutch per year, but if it dies on early stages brooding may be delayed again. Both parents incubate incubation period lasts 23–26 days. The chicks hatch almost naked and helpless in the same order as the eggs were laid. A fierce fight immediately begins between them over food, in which the older and stronger ones win. Most often, the younger ones die, and often only 2 older chicks (and sometimes even 1) survive in the brood. In the first days, the parents feed the chicks with regurgitated food, and then bring the whole prey. Chicks in a nest behave aggressively not only towards each other. Ornithologists who have happened to ring great egret chicks say that the chicks desperately resist and try to hit a person with their beak, aiming at the eyes.
The chicks fledge after 42–49 days, begin to fly well after 7 weeks, but for another 3–4 weeks they depend on their parents, after which the brood disintegrates. The mortality rate of young great egrets in the first year of life is very high and amounts to over 75%. Great white herons become sexually mature at the age of 2 years.
Lifespan
In nature, the average lifespan of great white herons is 15 years; in captivity it can reach up to 22 years.
The story of life at the Moscow Zoo
In our zoo, the only great white egret is kept along with other representatives of the order of storks in the New Territory in the Birds and Butterflies pavilion. In winter she lives in a warm indoor enclosure, in summer she lives outside.
Every day the heron receives about 500 g of food, which includes fish, meat, mice and frogs.
The history of this heron is very unusual. About 10 years ago she was brought from Anadyr in Chukotka (!), where she flew for the winter (!). How she got there and how she planned to spend the winter there is completely unclear. There are cases when birds find themselves in places completely uncharacteristic for them, brought, for example, by strong winds or storms. (Ornithologists call such cases “stays”). But on this day, according to eyewitnesses, there was no strong wind, no storm. Apparently there was some kind of glitch in the heron’s “program”. She got caught good people(otherwise she would certainly have died) and was brought to Moscow to the zoo, since then she (or he, the gender is still unknown) has been living here. He lives well, is in excellent shape, and every spring “produces” beautiful openwork aigrettes to the delight of his employees.