Stripe-backed bittern | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Pelecaniformes |
Family: | Ardeidae |
Genus: | Botaurus |
Species: | B. involucris |
Binomial name | |
Botaurus involucris (Vieillot, 1823) | |
The stripe-backed bittern (Botaurus involucris) is a South American bird species belonging to the family Ardeidae, which includes Herons, Egrets and Bitterns. It was formerly placed in the genus Ixobrychus. Commonly found near freshwater swamps, marshes, lake shores and streams, stripe-backed bitterns span over a wide distribution that divides into the northern and southern populations, spanning on both sides of the Andes. [2] Although increasingly recognized and researched worldwide, much life history details are lacking concerning this species, which remains understudied compared to its similar looking sister clade, including the least bittern (Botaurus exilis).
The stripe-backed bittern was formally described in 1823 by the French ornithologist Louis Vieillot under the binomial name Ardea involucris. [3] [4] Vieillot based his account on the "Garza varia" that had been described in 1805 by Spanish naturalist Félix de Azara in his Apuntamientos para la historia natural de los páxaros del Paragüay y Rio de la Plata. [5] The stripe-backed bittern was formerly placed in the genus Ixobrychus but when a molecular phylogenetic study of the heron family Ardeidae published in 2023 found that Ixobrychus was paraphyletic, Ixobrychus was merged into Botaurus . [6] [7] [8] The species is treated as monotypic: no subspecies are recognised. [7]
Stripe-backed bitterns are very small, averaging from 28 to 35 cm in length. [9] Their pale brown back is ornamented with both black and yellowish-beige streaks, the latter also running along their broad wings. [10] The colour patterns on their back complements the ones on their wings as to suppress obvious contrast between the two. Black stripes continue their way on the darker brown crown, while the underbelly is lighter brown and striped with white. [9] As for the beak, the colour can differ from pale green to orange. [10] This bittern species exhibits no sexual dimorphism, making it difficult to distinguish males from females. [10] Furthermore, juveniles are not phenotypically described in the literature. Discriminating gender and age for this species has proved to be a challenge, so has the simple quest to even observe them in the wild. Stripe-backed bitterns tend to adopt an upright stance in which they “freeze” in place to observe their surroundings, making it more efficient to hunt their preys. [2] When threatened, they respond by pointing their neck and bill skyward. This augments the difficulty to spot them easily. Following a solitary lifestyle, chances of finding them in groups are scarce but sights in pairs have been reported in the past. [10]
The stripe-backed bittern is easily confused with the least bittern. The most striking difference consist of the contrast between the dark coloured, completely streak less back of the least bittern, compared to its patterned wings. [11] Least bitterns also differ by the rufous coloration on the sides of their head, also present on the neck of females. [9]
Displaying a disjunct, yet wide distribution, stripe-backed bitterns are found on each side of the Andes. A northern population is distributed in large patches across South America, located in Colombia, Venezuela, Guyana, Suriname, French Guiana and the island of Trinidad, while a southern population is found in central and southern South America; in Paraguay, Uruguay, Argentina, Chile, southern Brazil and Bolivia. [9] In 2018, the presence of stripe-backed bitterns have also been confirmed in northeastern Ecuador, as well as in southeastern Peru. [9]
Freshwater sources are favoured as habitats for stripe-backed bitterns. Ideal ecological niches consist of highly vegetated reed beds, swamps, rushes, lakes and mountain streams, marshes, and rice fields. [9] [10] Such aquatic environments are essential in food acquisition, and in requirements for nest building.
The most prominent food source for stripe-backed bitterns, comprising half of their overall diet, are insects. More specifically, they preferably consume insects from the orders Odonata, Coleoptera, Hemiptera and Orthoptera. [12] The remaining half of their food intake is sourced from small fishes, crustaceans, and arachnids. [12] [13] Stripe-backed bitterns are diurnal birds. They tend to intensify their activities such as active hunting either early in the morning or in the afternoon, prioritizing rest at noon and at sunset. [12] They have been recorded to feed either alone, or in pairs. [13] Night feeding has also been reported, but only scarcely.
The reproduction cycle and breeding details of stripe-backed bitterns have not been extensively studied, and much of it is still unknown. What we do know is that this species is not a strong flier, and only does fly across short distances. Their nests are consequently not found high up in trees. Stripe-backed bitterns makes small nests of tightly bound reeds and stems, which are found above water level, among reeds. [10] Incubation period for eggs is unknown, and breeding seasons appear to vary widely based on location.
Stripe-backed bitterns have not been represented widely in the literature, especially due to the rarity of sight, as well as the scarcity of information concerning many of their life history traits. However, one topic has often resurged throughout history; the evolutionary explanation for stripe-backed bitterns’ distinct egg colour.
Ardeidae is a family of birds known to yield eggs of either elliptical or spherical shape, which are often pale blue in colour. [14] The translucent layer of their eggs, combining the commonly called cone and palisade layers, allows a glimpse into the blue or white inner shell. [14] The eggs of stripe-backed bitterns, uniquely, exhibit pale blue cone and palisade layers, covered by an outer translucent green layer. [14] Although recurrent observations/descriptions have been published, the evolutionary explanation for such a unique egg coloration within the Ardeidae bird family, remains unsolved to this day.
Sounds have been elaborately described and are sometimes the best way to determine the presence of stripe-backed bitterns, emitting calls through distinct, low-pitched ooks, or through gargling. [10] Territorial or warning vocalizations consist of four low-pitched short “huu” or “ook” notes, followed by a second type of vocalization; a faster and higher-pitched “g’u’u’u’a’a” gargle. [10]
This bittern is considered to be of least concern, due to its wide range, and its large, stable population. [15] As per information gathered by the IUCN Red List of threatened species, stripe-backed bitterns do not receive much conservation efforts, nor do they constitute a priority for outreach education programs, as their status is well anchored in the Least concerned section and is not foreseen to switch to a Vulnerable status anytime soon.
The American bittern is a species of wading bird in the heron family. It has a Nearctic distribution, breeding in Canada and the northern and central parts of the United States, and wintering in the U.S. Gulf Coast states, all of Florida into the Everglades, the Caribbean islands and parts of Central America.
The Eurasian bittern or great bittern is a wading bird in the bittern subfamily (Botaurinae) of the heron family Ardeidae. There are two subspecies, the northern race breeding in parts of Europe and across the Palearctic, as well as on the northern coast of Africa, while the southern race is endemic to parts of southern Africa. It is a secretive bird, seldom seen in the open as it prefers to skulk in reed beds and thick vegetation near water bodies. Its presence is apparent in the spring, when the booming call of the male during the breeding season can be heard. It feeds on fish, small mammals, fledgling birds, amphibians, crustaceans and insects.
Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 72 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genera Botaurus and Ixobrychus are referred to as bitterns, and, together with the zigzag heron, or zigzag bittern, in the monotypic genus Zebrilus, form a monophyletic group within the Ardeidae. Egrets do not form a biologically distinct group from herons, and tend to be named differently because they are mainly white or have decorative plumes in breeding plumage. Herons, by evolutionary adaptation, have long beaks.
The little bittern or common little bittern is a wading bird in the heron family, Ardeidae. Ixobrychus is from Ancient Greek ixias, a reed-like plant and brukhomai 'to bellow', and minutus is Latin for 'small'.
The cinnamon bittern or chestnut bittern is a small Old World bittern, breeding in tropical and subtropical Asia from India east to China and Indonesia. It is mainly resident, but some northern birds migrate short distances. This species was formerly placed in the genus Ixobrychus.
The yellow bittern is a small bittern. It is of Old World origins, breeding in the northern Indian Subcontinent, east to the Russian Far East, Japan and Indonesia. It is mainly resident, but some northern birds migrate short distances. It has been recorded as a vagrant in Alaska and there is a single sighting in Great Britain, from Radipole Lake, Dorset on November 23, 1962 – however, the British Ornithologists' Union has always considered this occurrence to be of uncertain provenance and currently it is not accepted onto the official British List.
The black bittern is a bittern of Old World origin, breeding in tropical Asia from Pakistan, India, Bangladesh and Sri Lanka east to China, Indonesia, and Australia. It is mainly resident, but some northern birds migrate short distances. This species was formerly placed in the genus Ixobrychus.
Botaurus is a genus of bitterns, a group of wading birds in the heron family Ardeidae.
Ixobrychus is a genus of bitterns, a group of wading bird in the heron family Ardeidae. It has a single representative species in each of North America, South America, Eurasia, and Australasia. The tropical species are largely resident, but the two northern species are partially migratory, with many birds moving south to warmer areas in winter.
The least bittern is a small heron, the smallest member of the family Ardeidae found in the Americas. This species was formerly placed in the genus Ixobrychus.
The tropical kingbird is a large tyrant flycatcher. This bird breeds from southern Arizona and the lower Rio Grande Valley of Texas in the United States through Central America, South America as far as south as central Argentina and eastern Peru, and on Trinidad and Tobago. Birds from the northernmost and southern breeding areas migrate to warmer parts of the range after breeding.
The Australasian bittern, also known as the brown bittern or matuku hūrepo, and also nicknamed the "bunyip bird", is a large bird in the heron family Ardeidae. A secretive bird with a distinctive booming call, it is more often heard than seen. Australasian bitterns are endangered in both Australia and New Zealand.
The black-goggled tanager is a species of bird in the family, Thraupidae. It is the only member of the genus Trichothraupis. It is found at low levels in forest and woodland in a large part of eastern and southern Brazil, eastern Paraguay and far north-eastern Argentina, with a disjunct population along the East Andean slope in Peru, Bolivia and far north-western Argentina. While generally common and widespread, and consequently considered to be of least concern by BirdLife International and IUCN, the population associated with the Andes is relatively local and uncommon.
The pinnated bittern, also known as the South American bittern, is a large member of the heron family (Ardeidae) found in the New World tropics. Like the other Botaurus bitterns, its plumage is mostly buffy-brown and cryptically patterned. Though it is a widespread species, it is rarely seen – presumably due to its skulking habits – and much about its life history remains little known.
The cocoi heron is a species of long-legged wading bird in the heron family Ardeidae found across South America. It has predominantly pale grey plumage with a darker grey crest. A carnivore, it hunts fish and crustaceans in shallow water.
The white-backed night heron is a species of medium-sized heron in the family Ardeidae, found in sub-Saharan Africa.
The New Zealand bittern is an extinct and enigmatic species of heron in the family Ardeidae. It was endemic to New Zealand and was last recorded alive in the 1890s.
The dwarf bittern is a species of heron in the family Ardeidae.
The sooty tyrannulet is a species of bird in the family Tyrannidae, the tyrant flycatchers. It is small, usually weighing 9 grams with a length of 12 centimeters, and has gray or brownish-grey feathers with black tail feathers. It is found in Argentina, Brazil, and Uruguay; also southern Paraguay. A small extension of its range is in southeastern Bolivia.
The black-backed bittern, also known as the black-backed least bittern or Australian little bittern, is a little-known species of heron in the family Ardeidae found in Australia and vagrant to southern New Guinea. Formerly lumped with the little bittern, it is one of the smallest herons in the world.
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