Egretta thula
Snowy Egret - Egretta thula
Habitat Snowy egrets prefer shallow salt water and freshwater areas for feeding. They are often found in salt marsh pools, wetlands, mud flats, ponds, mangroves, and tidal channels. They are most commonly found along the coast due to availability of food.
Range E. thula has a very wide range, extending from Northern California to areas of Tennessee and Kansas and even into areas of Chile and Argentina. They are especially found along the coasts of North America in California, the Carolinas, and the Gulf coast.
Description The snowy egret is an average size of 24 inches with up to a 3 1/2 foot wing-span. They have an all white plumage. Their most prominent features are their bright yellow feet and the bright yellow skin between their eyes. They have a thin, black bill as well as slim, black legs that contain a yellow stripe on the back. During breeding season, they possess long, white plumage on the back of their heads and their yellow features change to a brighter orange/red color. Snowy egrets are particularly vocal with their characteristic 'rah' call. Snowy egrets are also called snowy herons, little white egrets, and Brewster's egret.
Ecological Notes E. thula forages for its food, which includes: insects, fish, snakes, crustaceans, frogs, snails, worms, lizards, and rodents. They use frantic movements to startle their prey. These strategies include using their feet to stir the water or substrate, flicking their wings, raking and probing the substrate, walking rapidly, and dipping their bills in the water while in flight. However, like typical herons, they will wait until their prey comes close enough to strike. In the United States, snowy egrets typically nest between March and May. Males reach the nesting grounds first to establish nesting and display territory. Once females arrive, males perform a mating display. The males circle in the air then descend to a perch. On the perch, they point their bill upwards, bob their head up and down, and deliver a 'wah' call. Females build flat nests with sticks collected by the males. The nests are typically built in mangrove trees or woody shrubs. Typically, 2-6 eggs are laid.They are incubated for 20-24 days and fledged after 28-30 days. Both the male and female feed the young.
Personal Information Amanda Kriner and I spotted a snowy egret while we were birding on Pea Island, North Carolina in April of 2018. Amanda immediately identified it as a snowy egret due to the yellow coloring on the feet.
Journal Articles For information on Egretta thula
Hill, E.F., Henny, C.J. & Grove, R.A. 2008. Mercury and drought along the lower Carson River, Nevada: II. Snowy egret and black-crowned night-heron reproduction on Lahontan Reservoir, 1997–2006. Ecotoxicology 17, 117-131.
This article examines how high mercury levels and drought along the lower Carson River, Nevada affect reproduction rates in the snowy egret. Researchers found that in the drought period (2000-2004), all eggs containing ≥0.80 micrograms THg/g (total mercury) failed.
Benoit, L.K. & Askins, R.A. 1999. Impact of the spread of Phragmites on the distribution of birds in Connecticut tidal marshes. Wetlands 19, 194-208.
This article examines how the increasing growth of Phragmites affects the presence of birds that are typically found in the tidal marshes. These researchers found a negative correlation between the spread of Phragmites and the presence of snowy egrets. Phragmites grows in areas of flooding, so it may just be that the snowy egrets cannot penetrate it, making it an unsuitable habitat for them.
References Animal Diversity Web
Contributed by Danielle Bates - 2018