| Striated heron | |
|---|---|
.JPG) | |
| NominateButorides striata striata, Pantanal, Brazil | |
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Pelecaniformes |
| Family: | Ardeidae |
| Genus: | Butorides |
| Species: | B. striata |
| Binomial name | |
| Butorides striata | |
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| Range of the striated heron Year-round | |
| Synonyms | |
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Thestriated heron (Butorides striata) also known asmangrove heron orlittle green heron, is a smallheron, about 44 cm tall. It is mostlysedentary and noted for some interesting behavioural traits. The breeding habitat is in South America and theCaribbean. The striated heron was formerly considered to beconspecific with thelittle heron that is found in theOld World tropics from west Africa to Japan and Australia.
The striated heron wasformally described by the Swedish naturalistCarl Linnaeus in 1758 in thetenth edition of hisSystema Naturae. He placed it with the other herons in thegenusArdea and coined thebinomial nameArdea striata. Linnaeus specified thelocality asSuriname.[2][3] The specific epithet is fromLatinstriatus meaning "striated".[4] The striated heron is now one of four closely related species placed in the genusButorides that was described in 1852 by the English zoologistEdward Blyth.[5]This bird was long considered to beconspecific with the closely related North American species, thegreen heron, which is now usually separated asButorides virescens, as well as thelava heron of theGalápagos Islands (nowButorides sundevalli, but often included inButorides striata, e.g. byBirdLife International[6]); collectively they were called "green-backed heron".
Amolecular phylogenetic study of the genusButorides, submitted in 2023 as a master's thesis, found that the striated heron wasparaphyletic. To resolve the paraphyly, twentysubspecies of the striated heron were moved to a new species, thelittle heron, making the striated heron amonotypic species restricted to South America.[7][5]
The striated heron is 35–48 cm (14–19 in) in length, weighs 130–250 g (4.6–8.8 oz) and has a wing-span of 52–60 cm (20–24 in). The sexes are alike. The plumage is variable below, from mid grey to pinkish-purple or orangey toned.[8][9] Adults have a blue-grey back and wings, white underparts, a black cap, a dark line extends from the bill to under the eye and short yellow legs. Juveniles are browner above and heavily streaked below.
It is widespread in tropical and warm temperate South America, from central and southeasternPanama south toRío Negro Province inArgentina. It is generally a lowland bird, found in marshes, lakes and rivers, in Peru up to an altitude of 800 m, thus avoiding theAndes mountains.[8][9] InTrinidad and Tobago and in central Panama, it overlaps slightly in range with the closely relatedgreen heron andhybridises with it; hybrids are intermediate between the two species, generally much more purple-red below than typical striated herons.[10][11]
_with_fish_Rio_Napo_2.jpg)
These birds stand still at the water's edge and wait to ambush prey, but are easier to see than many small heron species. They mainly eat small fish, frogs and aquatic insects. They sometimes use bait, dropping a feather or leaf carefully on the water surface and picking fish that come to investigate.[12]
The nest is a platform of sticks measuring between 20–40 cm long and 0.5–5 mm thick. The entire nest measures some 40–50 cm wide and 8–10 cm high outside, with an inner depression 20 cm wide and 4–5 cm deep. It is usually built in shrubs or trees but sometimes in sheltered locations on the ground, and often near water. Theclutch is 2–5eggs, which are pale blue and measure around 36 by 28 mm.[13]
An adult bird was once observed in a peculiar and mysterious behaviour: while on the nest, it would grab a stick in its bill and make a rapid back-and-forth motion with the head, like a sewing machine's needle. The significance of this behaviour is completely unknown: While such movements occur in many other nesting birds where they seem to compact the nest, move the eggs, or dislodgeparasites, none of those seem to have been the purpose in this particular case.[13]
Young birds will give a display when they feel threatened, by stretching out their necks and pointing the bill skywards. How far this would deterpredators is not known.[13]
Widespread and generally common, the striated heron is classified as a species ofleast concern by theIUCN; this holds true whether thelava heron is included inButorides striata or not.[6]
