Female egrets generally lay 3-6 eggs and both parents incubate the eggs for approximately 22-25 days. Upon hatching, the young nestling is a grayish color. It has a dark blue area around the eyes and the bill is a pale, pinkish gray. Once the eggs are fully hatched, the adults remove the eggshells from the nest. The hatchlings are covered in white down except for their wings. Pinfeathers appear by the first week. Juvenal feathers emerge on the body and wings by 2 to 3 weeks of age. Leg color varies from yellow to black. The hatchlings have a yellow colored bill tipped with black until five weeks of age, when the entire bill changes to black. Both parents brood their semialtricial young for the first 10 days. After 10 days, only one parent remains in the nest for 50% of the time. This generally lasts until the nestlings become 14 days old. The nestlings leave the nest after two weeks, but some may leave the nest as early as 10 days (Howell 1995; Parsons 2000).
Egretta thula is a medium-sized heron with a delicate build. Adult egrets generally measure between 56 to 66 cm and have a wingspan of approximately 100 cm. Egrets average 370 g in weight and the males tend to be slightly larger than the females. Egretta thula has entirely white plumage, a long, slender black bill, bright yellow lores, and long, slender black legs with bright yellow feet. Eyes are yellow. Breeding adults develop long, delicate plumes off their breast and are also characterized by their change in foot color, from yellow to orange. There are no overall differences in appearance between breeding populations, however, populations studied in North America and Central America are found to have a larger bill than egrets of South America.
Average mass: 370 g.
Average length: 56-66 cm.
Average wingspan: 100 cm.
Sexual Dimorphism: male larger
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 314 g.
Egretta thula has a 71.6% mortality rate during its first year and a 31.4% mortality rate during years 2 to 17. The oldest egret was recorded in Utah and lived 22 years, 10 months. Snowy egrets generally live between 2 and 17 years. Egretta thula has been subject to nematode parasitism, which causes death. Starvation and inclement weather are likely causes of death for young nestlings.
Range lifespan
Status: wild: 22 (high) years.
Typical lifespan
Status: wild: 2 to 17 years.
Egretta thula generally prefers an environment of shallow water inlets for feeding purposes. Salt-marsh pools, tidal channels, shallow bays, and mangroves are among the most preferred habitats in North America. Habitats are most common among coastal areas and islands due to the availability of stable and abundant food sources. During the winter months, egrets migrate to the Caribbean to nest and roost in the mangroves. The Caribbean is home to other favorable egret habitats including salt-water lagoons, freshwater swamps, grassy ponds, beaches, shallow reef areas, flooded rice fields, and wet grassy meadows. Throughout Central America, E. thula prefers mainly lowland areas near freshwater swamps, lakes, and large river mouths. South American species also prefer coastal mangroves, mudflats, and swamps rather than highland areas.
Habitat Regions: temperate ; tropical ; terrestrial
Wetlands: marsh ; swamp
Other Habitat Features: riparian ; estuarine
Egretta thula is found throughout North, Central, and South America as well as the Caribbean. It breeds in coastal and inland wetlands, but its range limits have changed over time due to the effects of hunting and habitat loss. Small breeding populations are located in Nova Scotia, Canada, and more heavily populated locations are found across the United States. Egretta thula is common among northern Nevada, Utah, and southeastern states, especially Florida and states bordering the Gulf of Mexico. This egret is most prevalent throughout Mexico, Central America, and South America. Egretta thula is a partially migratory species, as it relocates from its northern habitats of the United States and Canada to its winter ranges located in Mexico, Central America, South America, the West Indies, and Bermuda. Snowy Egrets begin their northward migration in early March and depart in September to migrate to their wintering areas.
Biogeographic Regions: nearctic (Native ); neotropical (Native ); oceanic islands (Native )
Egretta thula prefers foraging habitats near bodies of shallow water, which are ideal for food sources. Its broad diet consists of earthworms, annelid worms, aquatic and terrestrial insects, crabs, shrimp, crayfish, snails, freshwater and marine fish, frogs, toads, lizards and snakes. The egret's diet is generally composed of 75% fish and 25% crustaceans. This egret has the widest range of foraging behaviors when compared to other herons. Food capturing is performed by pecking, walking slowly or quickly, running, hopping, hovering, and "disturb and chase" behaviors. Snowy egrets primarily feed during the early morning and evening hours. Egrets occasionally engage in group flights to fly to far-away foraging environments. Otherwise, egrets independently fly approximately 3 km from their colonies to foraging sites. However, foraging in larger groups allows for greater success in finding substantial food sources and helps provide protection from predators.
Animal Foods: amphibians; reptiles; fish; insects; mollusks; terrestrial worms
Primary Diet: carnivore (Piscivore )
Egretta thula serves as a biological indicator of ecosystem health and habitat quality. In marshes, bays, and swamp habitats, the absence of egrets may reflect disturbances in the ecosystem, such as pollution, contamination of water, habitat loss, or human disturbance. In some habitats, researchers have sampled eggs and feathers to test levels of environmental contamination. Egrets are positioned at the top of the food chain, thus their decline may also infer a decline of other species, such as fish or insects. Egretta thula is a highly social bird and will not attack humans or disturb other bird species in its habitat.
In the United States from 1880 to 1910, adult egrets were shot by plume hunters. Egretta thula was hunted for its delicate back plumes that were used to decorate women's hats and clothing. In 1886, plumes were valued at $32 per ounce, which was twice the price of gold at the time. In 1910, most hunting ceased due to citizens' requests to stop the slaughter of egrets. However, hunting still continued in Central and South America due to the European demand for plumes.
Positive Impacts: body parts are source of valuable material
There are no known adverse affects of snowy egrets on humans.
Populations appear to be declining along the Atlantic coast due to pollution and competition with other bird species. Egretta thula is at risk because of chemical contamination and the decline of wetland environments. Snowy egrets depend on wetland areas for food. Eggs in agricultural areas are contaminated by pesticides, which cause death. Egrets have also died from consumption of styrofoam, plastics, and lead found in the environment. Oil spills have also caused mortality. Egretta thula has been protected in North America since 1916 under the Migratory Bird Treaty Act. The Migratory Bird Treaty Act prohibited the hunting of egrets for their plumes, thus allowing them to return to their previous levels of abundance.
US Migratory Bird Act: protected
US Federal List: no special status
CITES: appendix iii
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Egretta thula communicates through sound vocalizations and posture. Young birds produce soft, buzzing calls and mature birds produce high and low-pitched calls. High-pitched calls signify plentiful foraging sites and low-pitched calls signify aggressive situations. Greeting calls are common among egrets. Only males tend to use high sound vocalizations, especially to attract a female mate. Communication sounds are also used to defend the territory surrounding the nest. An egret's upright posture with fully erect feathers marks the onset of an attack on another bird.
Communication Channels: visual ; acoustic
Perception Channels: visual ; tactile ; acoustic ; chemical
Similar species to Egretta thula include Egretta caerulea, little blue heron, and Egretta garzetta, little egret. Little blue herons have completely white plumage, but can be distinguished from E. thula by their gray lores. Little egrets are larger and stockier than E. thula and also have longer legs, bill, and neck.
Egretta thula has shown an increased preference for island nest sites in urbanized, coastal estuaries. Egrets choose urbanized locations over isolated locations, because isolated locations have more predators. Egrets use flight to escape predation from terrestrial animals and they are known to have innate recognition and avoidance of poisonous snakes.
Known predators include: Procyon lotor (racoon), Bubo virginianus (great-horned owl), Strix varia (barred owl), Corvus brachyrhynchos (American crow), Corvus ossifragus (fish crow), Alligator mississippiensis (American alligator), Pantherophis obsoletus (rat snake) and Buteogallus anthracinus (common black-hawk).
Known Predators:
Breeding begins in late March or early April when the male egrets perform flight displays and sound vocalizations to attract female mates. The most common courtship display is the "Stretch" display, in which the male pumps his body up and down with his bill pointed towards the sky. The male then produces a call to attract females. The changing foot color from yellow to reddish orange indicates the beginning of breeding behaviors. Breeding adults are also characterized by the distinctive display of long, delicate plumes off their breasts. Once a male finds a mate, the pair performs sexual displays and eventually builds a nest for their offspring.
Mating System: monogamous
The male and female pair-bond is maintained through a series of sexual displays. Breeding begins in March or early April. Female egrets usually build nests in the territories defended by the males. Nests are often built in isolated, estuarine habitats and can be located either on the ground or as high as 30 feet in the trees. The nests are composed of woven twigs and small sticks that female egrets collect from the ground or steal from other nests. Egretta thula may also reuse old nests. These egrets are highly social nesters and build nests close to other egrets or herons. No preliminary rituals are performed prior to copulation, which takes place in the nest. Males stand on the backs of females and cloacal cavities come into contact during copulation to fertilize the eggs. The average duration of contact is 10 seconds. Females lay 3-6 eggs at a time (on average); eggs have a pale, greenish blue color. Incubation lasts 24 days on average and the chicks usually fledge 14 days after hatching. Young reach reproductive maturity after 1 to 2 years.
Breeding season: The breeding season begins in March or early April.
Range eggs per season: 2 to 8.
Average eggs per season: 3-6.
Range time to hatching: 22 to 29 days.
Average time to hatching: 24 days.
Range fledging age: 10 to 25 days.
Average fledging age: 14 days.
Range age at sexual or reproductive maturity (female): 1 (low) years.
Average age at sexual or reproductive maturity (female): 2 years.
Range age at sexual or reproductive maturity (male): 1 (low) years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Average eggs per season: 4.
Both parents incubate the eggs and feed the nestlings by dropping food into the nest. Once the eggs hatch, parents remove the eggshells from the nest. Both parents brood their altricial young continuously until the hatchlings are 10 days old. From 10 to 14 days, only one parent is present in the nest to brood the young. After 10 days, parents are only in the nest 50% of the time. However, when storms occur, the young are brooded continuously. During the first five days after hatching, parents feed their young by regurgitating food onto the nest floor for the hatchlings to eat. Sometimes the parents' bill is placed directly into the hatchlings' mouth and food is regurgitated. The younger nestlings are fed before the older hatchlings. Adults keep the nest clean by dumping waste over the sides of the nest.
Parental Investment: no parental involvement; altricial ; pre-fertilization; pre-hatching/birth (Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)
Smaller (20-27 inches) than North America’s other light-colored herons and egrets, the Snowy Egret is most easily identified by its black bill, black legs, yellow feet, and regal breeding plumes. Other field marks include an all-white body, short tail, and small yellow skin patch on the face. Male and female Snowy Egrets are similar to one another in all seasons. The Snowy Egret breeds along the east coast of the United States north to Maine and locally in the interior southeast and west. Coastal birds are non-migratory, while interior birds migrate to the Atlantic and Gulf coasts, the Pacific coast of California and in the interior from northern Mexico south to Panama. Other non-migratory populations occur along both coasts of Mexico and Central America as well as in the West Indies. Snowy Egrets live in and around small bodies of water. In summer, Snowy Egrets nest in colonies, called ‘rookeries,’ in trees surrounding lakes and ponds. This species utilizes similar habitats during the winter. Snowy Egrets mainly eat fish, but may also take crustaceans and small vertebrates (such as frogs, lizards, and mice) when the opportunity arises. Snowy Egrets may be best observed wading in shallow water, where they may be seen plunging their bills into the water to catch fish. It is also possible to see Snowy Egrets at their rookeries, especially when they return to roost at sunset, or while flying with their feet extended and their necks pulled in. Snowy Egrets are primarily active during the day.
Smaller (20-27 inches) than North America’s other light-colored herons and egrets, the Snowy Egret is most easily identified by its black bill, black legs, yellow feet, and regal breeding plumes. Other field marks include an all-white body, short tail, and small yellow skin patch on the face. Male and female Snowy Egrets are similar to one another in all seasons. The Snowy Egret breeds along the east coast of the United States north to Maine and locally in the interior southeast and west. Coastal birds are non-migratory, while interior birds migrate to the Atlantic and Gulf coasts, the Pacific coast of California and in the interior from northern Mexico south to Panama. Other non-migratory populations occur along both coasts of Mexico and Central America as well as in the West Indies. Snowy Egrets live in and around small bodies of water. In summer, Snowy Egrets nest in colonies, called ‘rookeries,’ in trees surrounding lakes and ponds. This species utilizes similar habitats during the winter. Snowy Egrets mainly eat fish, but may also take crustaceans and small vertebrates (such as frogs, lizards, and mice) when the opportunity arises. Snowy Egrets may be best observed wading in shallow water, where they may be seen plunging their bills into the water to catch fish. It is also possible to see Snowy Egrets at their rookeries, especially when they return to roost at sunset, or while flying with their feet extended and their necks pulled in. Snowy Egrets are primarily active during the day.
The snowy egret (Egretta thula) is a small white heron. The genus name comes from Provençal French for the little egret, aigrette, which is a diminutive of aigron, 'heron'. The species name thula is the Araucano term for the black-necked swan, applied to this species in error by Chilean naturalist Juan Ignacio Molina in 1782.[3]
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.[4] They were hunted for these plumes and this reduced the population of the species to dangerously low levels.[5] Now protected in the United States by law, under the Migratory Bird Treaty Act, this bird's population has rebounded.
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.[6] Immature snowy egrets have duller, greenish legs.
Measurements:[7]
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.[6] The snowy egret has occurred as a vagrant in Europe, in Iceland, Scotland and the Azores.[8] It has also been recorded in South Africa.[9]
The birds eat fish, crustaceans (such as crabs, shrimp and crayfish),[10] insects, small reptiles (such as lizards and snakes),[11] snails, frogs, toads[12] and worms (especially earthworms and other annelids).[13] 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.[5]
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.[5]
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.[2] The deposits were dated to the Late Pleistocene.[14][15][16][17]
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.[5] 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".[1]
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Head shot
Plumage displayed
Full breeding plumage
With chicks
Tayrona national park, Colombia
In flight
In flight
On the hunt, Daytona Beach, Florida, United States
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Ponce Inlet Beach, Florida, United States.
A snowy egret and its hatchlings in St. Augustine, FL.
Snowy egret chicks in St. Augustine, FL
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Snowy egret hunting in Queens, New York
Snowy Egret walking along water's edge while looking for food
A Snowy Egret Catches a fish The snowy egret (Egretta thula) is a small white heron. The genus name comes from Provençal French for the little egret, aigrette, which is a diminutive of aigron, 'heron'. The species name thula is the Araucano term 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.
