Snowy Egret (Egretta thula)

Snowy Egret


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. 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.

Distribution And Habitat

The Snowy Egret occurs through most of the Western Hemisphere including the West Indies (Raffaele and others 1998). It is a common and permanent resident in Puerto Rico and can be seen regularly at the Boquerón Nature Reserve and the salt fl ats of Cabo Rojo (Oberle 2018). It is also present on Culebra and Vieques islands (Ventosa-Febles and others 2005), in the latter being common during winter and spring, uncommon in fall, and rare in summer (Gemmill 2015). Habitat includes mostly freshwater swamps, riverbanks (Raffaele and others 1998), lagoons, marshes, ponds, mangroves, and salt fl ats (Oberle 2018). The atlas fieldwork yielded a total of 232 records within 158 hexagons or 33 percent of the 479 total hexagons (see map). Of the 158 where this species was found, breeding met the atlas definition of confirmed in 8 percent (12) of the hexagons and probable in 1 percent (2), while the species was observed in 91 percent (144) of the hexagons but without evidence of breeding (see map). Snowy Egret distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in Puerto Rico. Note: percentages may not total 100 due to rounding.

Snowy Egret Distribution

Breeding Habits

Previously published reports indicate that the Snowy Egret breeds from April to July and also in October (Raffaele and 149Snowy Egret/Garza Blancaothers 1998). Nesting is often colonial with other heron species (Biaggi 1997, Oberle 2018, Raffaele and others 1998), and the nest is made of sticks and usually built in mangroves and swamps (Oberle 2018, Raffaele and others 1998). Atlas results show that this species breeds from February to July with the most breeding activity during March, April, and June (see chart). Overall, the breeding activity peaks during March and June, and mostly takes place within the subtropical moist forest life zone (see chart). Results show that this species breeds mostly in lowlands within the subtropical moist forest life zone (64 percent of the hexagons) (see table), but it also breeds in subtropical wet and subtropical dry forest life zones as well (29 and 7 percent of the hexagons, respectively) (see table and map).


The current overall population trend of the Snowy Egret is described as increasing. However, some populations may be stable, and others have unknown trends (Wetlands International 2012). This species is currently listed as a species of least concern by the IUCN (BirdLife International 2016). Locally, this species is not listed in any of the threatened categories of PRDNER and USFWS. In Puerto Rico, the Snowy Egret has a protected habitat in land of 4 percent or 15 km2 of the total area covered by the hexagons where evidence of breeding was found for this species (335 km2).