The snowy egret (Egretta thula) is a small white heron. The genus name comes from the Provençal French for the little egret aigrette, a diminutive of aigron, «heron». The species name thula is the Araucano for the black-necked swan, applied to this species in error by Chilean naturalist Juan Ignacio Molina in 1782.
The snowy egret is the American counterpart to the very similar Old World little egret, which has become established in the Bahamas. At one time, the plumes of the snowy egret were in great demand as decorations for women’s hats. They were hunted for these plumes and this reduced the population of the species to dangerously low levels. Now protected in the United States by law, under the Migratory Bird Treaty Act, this bird’s population has rebounded.
Description
Adult snowy egrets are entirely white apart from the yellow lores between the long black bill and the eye, black legs, and bright yellow feet. The nape and neck bear long, shaggy plumes known as aigrettes. Immature snowy egrets have duller, greenish legs.
Similar species
It can be confused with the Great egret (Ardea alba), but this is larger, with a longer neck and a yellow bill. It also resembles the Little Blue Heron (Egretta caerulea), but these differ because they have a bluish-gray bill with black and greenish legs.
Regional differences
Two subspecies E. t. thula and E. t. brewsteri. The latter is located in Colombia and is differentiated by being larger.
Taxonomy
Form a superspecies with Egretta garzetta.
Distribution and habitat
The snowy egret is native to North, Central and South America. It is present all year round in South America, ranging as far south as Chile and Argentina. It also occurs throughout the year in the West Indies, Florida and coastal regions of North and Central America. Elsewhere, in the southern part of the United States, it is migratory, breeding in California, Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Louisiana and Mississippi. It is found in wetlands of many types; marshes, riverbanks, lakesides, pools, salt marshes and estuaries. It is not found at high altitudes nor generally on the coast. The snowy egret has occurred as a vagrant in Europe, in Iceland, Scotland and the Azores.
Diet
The birds eat fish, crustaceans, insects, small reptiles, snails, frogs, worms and crayfish. They stalk prey in shallow water, often running or shuffling their feet, flushing prey into view by swaying their heads, flicking their wings or vibrating their bills. They may also hover, or «dip-fish» by flying with their feet just above the water surface. Snowy egrets may also stand still and wait to ambush prey, or hunt for insects stirred up by domestic animals in open fields. They sometimes forage in mixed species groups.
Breeding
Snowy egrets breed in mixed colonies, which may include great egrets, night herons, tricolored herons, little blue herons, cattle egrets, glossy ibises and roseate spoonbills. The male establishes a territory and starts building the nest in a tree, vines or thick undergrowth. He then attracts a mate with an elaborate courtship display which includes dipping up and down, bill raising, aerial displays, diving, tumbling and calling. The immediate vicinity of the nest is defended from other birds and the female finishes the construction of the nest with materials brought by the male. It is constructed from twigs, rushes, sedges, grasses, Spanish moss and similar materials and may be 15 in (38 cm) across. Up to six pale bluish-green eggs are laid which hatch after about 24 days. The young are altricial and covered with white down when first hatched. They leave the nest after about 22 days.
Fossil finds
Fossils of the snowy egret have been reported from the Talara tar seeps of Peru and in Bradenton in Manatee County and Haile XIB in Alachua County in Florida, United States. The deposits were dated to the Late Pleistocene.
Reproduction
Signs of reproduction have been found between April and July in the United States, from March to May in Puerto Rico, between November and January in Ecuador, from October to November in southeastern Brazil, from August to October in Venezuela, and between March and April. In colombia. It generally forms very large colonies with hundreds of nests, which it builds with sticks near water at low levels in trees or shrubs. It generally lays 2-4 pale blue green eggs that hatch for about 18 days. Young remain in nest for approximately 30 days.
Behavior
It is a bird that feeds alone or in groups with other species of herons. It is one of the most active day herons and uses a wide variety of techniques to capture its prey. Sometimes it forages by shaking the water with one leg in order to catch fish and other animals that are found under the mud. It can also be seen capturing insects that scare off livestock. North American populations migrate after the reproductive period to the Caribbean, Central America and northern South America. Little is known about the movements of populations in southern South America but there is some evidence that they also carry out movements after the breeding period.
Conservation Status
In the early twentieth century, the snowy egret was hunted extensively for their long breeding plumes that fashionable ladies wore on their hats. This trade was ended in 1910 in North America but continued for some time in Central and South America. Since then populations have recovered. The bird has a very wide range and the total population is large. No particular threats have been recognised and the population trend seems to be upwards, so the International Union for Conservation of Nature has assessed its conservation status as being of «least concern».
Vocalization/ Song
https://www.xeno-canto.org/222668
