Summary

Did you know?

Snowy Egrets use their bright yellow feet to stir up sediments in the water and frighten prey out of hiding places (Willard 1977 and Hom 1983 cited in Parsons and Master 2000).

State Ranking Justification

The Snowy Egret is known to occur in nine counties in New York State including Bronx, Erie, Kings, Nassau, New York, Queens, Richmond, Suffolk, and Westchester counties (McGowan and Corwin InPress, New York Natural Heritage Program 2007). After the population reached its peak during a period of fluctuation in the mid-1970s, numbers appear to have declined slightly in recent years (Peterson cited in Andrle and Carroll 1988). In general, Snowy Egret populations are declining along the Atlantic Coast (Parsons and Master 2000) and nationwide (Kushlan et al. 2002 cited in McGowan and Corwin In Press).

Short-term Trends

Brown et al. (2001) discovered that there were approximately 904 nesting pairs of Snowy Egrets on Long Island between 1974 and 1995. The number of nesting pairs in Jamaica Bay Wildlife Refuge declined between 1976 and 1993 (Brown et al. 2001). The species is also found in the Niagara Basin (New York Breeding Bird Atlas 2000-2005, New York Natural Heritage Program 2007) and the statewide population of Snowy Egrets in recent years has undergone cycles of growth and decline (McGowan and Corwin In Press). The first Breeding Bird Atlas in New York (1980-1985) reported Snowy Egrets in 34 probable or confirmed breeding blocks (Andrle and Carroll 1988), while the second Atlas (2000-2005) reported them in 29 probable or confirmed breeding blocks (McGowan and Corwin In Press). This represents a 15% decline over the two atlases in the number of confirmed or probable breeding blocks where Snowy Egrets were found.

Long-term Trends

The first records of Snowy Egret breeding in New York occurred in the 1880s, in limited numbers, on the coastal islands of Long Island (McGowan and Corwin In Press). During this time frame and the early 1900s, Snowy Egrets became extirpated from the state due to overhunting for their plumes, which were in high demand for the hat trade. They were listed as extirpated in the state in the 1920s (Peterson 1988 cited in Andrle and Carroll 1988). They were first seen breeding again in Suffolk County in 1949 following legislation which protected migratory birds (Bull 1974). In the mid-1970s, the population reached its peak, and after a period of fluctuation during the 1970s and 1980s, now averages 780 nesting pairs per season (McGowan and Corwin In Press).

Conservation and Management

Threats

Habitat loss has been noted as the greatest threat to this species. In addition, complete information on breeding and foraging habitat requirements is not currently available (McCrimmon 2006). On Long Island, threats include flooding, erosion, human activity, and predation. Human activities include boating and fishing, dredge spoil deposition, pedestrians, jet skiers, ORV and other vehicle use, development, oil spills, contaminants, vandalism, and invasive species. Known predators that currently pose a threat to populations are crows, gulls, raccoons, dogs, feral cats, rats, and others (New York Natural Heritage Program 2007).

Conservation Strategies and Management Practices

As habitat loss is the largest known threat to Snowy Egrets, continuing to protect lands such as the Jamaica Bay Wildlife Refuge and other managed areas is important to the conservation of this species and other colonial waterbirds (Brown et al. 2001). Limiting predation and human activity through the use of predator exclosures, visitor education, and by posting restricted signs in breeding and foraging areas would also be beneficial. Any habitat restoration efforts should consider increasing the availability of pool and open water habitat, as foraging habitat availability may be a limiting factor for egrets (Trocki and Paton 2006). Another consideration for the management of breeding Snowy Egrets is the use of buffers around colonies to reduce flushing responses to human disturbance (Peters and Otis 2006). Vehicle disturbances, especially in undeveloped areas, have been shown to cause a decline in foraging rates for this species, with seasonal differences in behavioral response (Stolen 2003, Traut and Hostetler 2003). This suggests that buffer zones could provide additional protection.

Research Needs

Further studies are needed to understand how this species is affected by habitat loss from human activity. While many existing and potential threats have been identified, further knowledge about how these threats interplay and affect Snowy Egret behavior and population viability would better inform management decisions (Peters and Otis 2006). More complete information on breeding and foraging habitat requirements, reproductive ecology, and life history is needed for this species as well (McCrimmon 2006).

Habitat

Habitat

Snowy Egrets inhabit open edges of rivers, lakes, salt marshes, salt pannes, brackish interdunal swales, marine intertidal zones and maritime beaches and shrubland in New York (Budliger and Kennedy 2005, New York Natural Heritage Program 2007). They nest in dense scrub thickets on coastal sand dunes close to feeding areas, usually 3-10 feet off the ground (Bull 1974 in Andrle and Carroll 1988).

Associated Ecological Communities

• Brackish interdunal swales (guide)
  Temporarily tidally flooded temperate marshes in interdunal swales dominated by salt-tolerant graminoids. Individual swales occur as small patches positioned between fore-, primary and secondary dunes in a maritime dunes system, typically on barrier islands.
• High salt marsh (guide)
  A coastal marsh community that occurs in sheltered areas of the seacoast, in a zone extending from mean high tide up to the limit of spring tides. It is periodically flooded by spring tides and flood tides. High salt marshes typically consist of a mosaic of patches that are mostly dominated by a single graminoid species.
• Low salt marsh (guide)
  A coastal marsh community that occurs in sheltered areas of the seacoast, in a zone extending from mean high tide down to mean sea level or to about 2 m (6 ft) below mean high tide. It is regularly flooded by semidiurnal tides. The mean tidal range of low salt marshes on Long Island is about 80 cm, and they often form in basins with a depth of 1.6 m or greater.
• Marine rocky intertidal (guide)
  A community inhabiting rocky shores that are washed by rough, high-energy ocean waves. Characteristic organisms are attached marine algae, mussels, sea stars, urchins, and barnacles that can withstand the impact of the waves and periodic desiccation. Examples of this community in New York typically have gently sloping rocky shores comprised of boulders (0.25 to 3 m diameter) and/or cobbles (6.4 to 25 cm). Bedrock outcrops may be present in a few examples, but not to the extent or as steep as those described in other New England states, such as Maine. The community is typically rich in species. Attached organisms cover usually more than 60% of the substrate, especially at the lower intertidal zone.
• Maritime beach (guide)
  A community with extremely sparse vegetation that occurs on unstable sand, gravel, or cobble ocean shores above mean high tide, where the shore is modified by storm waves and wind erosion.
• Maritime shrubland (guide)
  A shrubland community that occurs on dry seaside bluffs and headlands that are exposed to offshore winds and salt spray.
• Salt panne (guide)
  A shallow depression in a salt marsh where the marsh is poorly drained. Pannes occur in both low and high salt marshes. Pannes in low salt marshes usually lack vegetation, and the substrate is a soft, silty mud. Pannes in a high salt marsh are irregularly flooded by spring tides or flood tides, but the water does not drain into tidal creeks. After a panne has been flooded the standing water evaporates and the salinity of the soil water is raised well above the salinity of sea-water.

Associated Species

• Great Egret (Ardea alba) (guide)
• Cattle Egret (Bubulcus ibis) (guide)
• Piping Plover (Charadrius melodus) (guide)
• Little Blue Heron (Egretta caerulea) (guide)
• Tricolored Heron (Egretta tricolor) (guide)
• American Oystercatcher (Haematopus palliatus)
• Herring Gull (Larus argentatus)
• Great Black-backed Gull (Larus marinus)
• Laughing Gull (Leucophaeus atricilla) (guide)
• Yellow-crowned Night-Heron (Nyctanassa violacea) (guide)
• Black-crowned Night-Heron (Nycticorax nycticorax)
• Double-crested Cormorant (Phalacrocorax auritus)
• Glossy Ibis (Plegadis falcinellus) (guide)
• Black Skimmer (Rynchops niger) (guide)
• Roseate Tern (Sterna dougallii) (guide)
• Forster's Tern (Sterna forsteri) (guide)
• Common Tern (Sterna hirundo) (guide)
• Least Tern (Sternula antillarum) (guide)

Range

New York State Distribution

The Snowy Egret is confirmed from nine counties in New York State including Bronx, Erie, Kings, Nassau, New York, Queens, Richmond, Suffolk, and Westchester counties (McGowan and Corwin InPress, New York Natural Heritage Program 2007).

Global Distribution

The Snowy Egret is known to breed in northern California, southern Idaho, Kansas, the lower Mississippi Valley, and Gulf and Atlantic coasts north to Maine, south through Mexico and the Antilles to South America (Spendelow and Patton 1988 cited in Nature Serve 2007). Wintering grounds include northern California, southwestern Arizona, the Gulf Coast, and South Carolina southward through the breeding range. In the United States, areas with the highest densities in winter include the Gulf Coast along the Texas-Louisiana border, the mouth of the Mississippi River, the lower Colorado River, and Florida (Root 1988 cited in Nature Serve 2007). Snowy Egrets may occur irregularly outside usual range, and have been observed a few times in Hawaii (Nature Serve 2007).

Best Places to See

• Pine Marsh (Nassau County)
• North and South Brother Islands
• Hoffman Island (Richmond County)

Identification Comments

Identifying Characteristics

The Snowy Egret is a medium-sized, white heron that is 56-66 cm in length and has a wingspan of 100 cm and a body mass of 370 g. They have black legs with yellow feet and a black bill (Parsons and Master 2000). During breeding season, long, white plumes trail from the throat and the rump. They are known to nest in colonies with others of the same species or another heron species (Budliger and Kennedy 2005). They nest in trees or shrubs or, in some areas, on the ground or in marsh vegetation (Spendelow and Patton 1988 cited in Parsons and Master 2000). Clutch size is 3-5 pale blue-green eggs which are incubated for 20-24 days (Budliger and Kennedy 2005). Vocalizations include a raspy "raarr" or nasal "hraaa" (Sibley 2000) and low croaks and a bouncy "wulla-wulla-wulla" on breeding grounds (Budliger and Kennedy 2005).

Diet

Snowy Egrets eat small fishes, frogs, lizards, snakes, crustaceans, worms, snails, and insects (Palmer 1962 cited in Nature Serve 2007). One New Jersey study showed that this species seems to prefer to forage in wadeable, shallow pools with high prey densities (Master et al. 2005).

Best Time to See

On the coast, this species is rare before late March and after November (New York Natural Heritage Program 2007).

Similar Species

• Great Egret (Ardea alba) (guide)
  The Great Egret is 38 cm longer than the Snowy Egret, so their greatest difference is size (Nature Serve 2007). In addition, the Snowy Egret has a black bill and yellow feet, while the Great Egret has a yellow bill and black feet (Budliger and Kennedy 2005).
• Little Blue Heron (Egretta caerulea) (guide)
  The Little Blue Heron has a yellow-orange bill and legs instead of a black bill and legs with yellow feet like the Snowy Egret (Budliger and Kennedy 2005).

Snowy Egret Images

Taxonomy

Snowy Egret
Egretta thula (Molina, 1782)

• Kingdom Animalia
  • Phylum Craniata
    • Class Aves (Birds)
      • Order Pelecaniformes (Pelicans and Cormorants)
        • Family Ardeidae (Herons, Bitterns, and Egrets)

Additional Resources

References

American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

Andrle, R. F., and J. R. Carrol, editors. 1988. The atlas of breeding birds in New York State. Cornell Univ., Ithaca, New York. 551 pp.

Brown, K.M., J.L. Tims, R.M Erwin, and M.E. Richmond. 2001. Changes in the nesting populations of colonial waterbirds in Jamaica Bay Wildlife Refuge, New York, 1974-1998. Northeastern Naturalist 8(3): 275-292.

Budliger, R.E., and G. Kennedy. 2005. Birds of New York State. Lone Pine Publishing, Auburn, WA. 384pp.

Bull, John. 1974. Birds of New York State. Doubleday, Garden City, New York. 655 pp.

Findholt, S. L. 1984. Organochlorine residues, eggshell thickness, and reproductive success of snowy egrets nesting in Idaho. Condor 86:163-169.

Fleury, B. E., and T. W. Sherry. 1995. Long-term population trends of colonial wading birds in the southern United States: the impact of crayfish aquaculture on Louisiana populations. Auk 112:613-632.

Master, T.L., J.K. Leiser, K.A. Bennett, J.K. Bretsch, and H.J. Wolfe. 2005. Patch selection by Snowy Egrets. Waterbirds 28 (2): 220-224.

McCrimmon, D.A. 2006. Species group report for colonial nesting herons. Pages 33-42 of Appendix A1, Species group reports for birds in: New York State comprehensive wildlife conservation strategy. New York Department of Environmental Conservation. Albany NY.

McGowan, K.J. and K. Corwin, eds. 2008. The Second Atlas of Breeding Birds in New York State: 2000-2005. Cornell University Press, Ithaca, NY. 688 pp.

National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.

NatureServe. 2007. NatureServe Explorer: An online encyclopedia of life [web application]. Version 6.1. NatureServe, Arlington, Virginia. Available http://www.natureserve.org/explorer. (Accessed: October 26, 2007).

New York Natural Heritage Program. 2007. Biotics Database. Albany, NY.

New York Natural Heritage Program. 2023. New York Natural Heritage Program Databases. Albany, NY.

New York State Breeding Bird Atlas 2000 [Internet]. 2000 - 2005. Release 1.0. Albany (New York): New York State Department of Environmental Conservation. [updated 2007 Jun 11; cited 2007 Dec 08]. Available from: http://www.dec.ny.gov/animals/7312.html.

New York State Breeding Bird Atlas. 1985. Final breeding bird distribution maps, 1980-1985. New York State Department of Environmental Conservation, Wildlife Resources Center. Delmar, NY.

Palmer, R. S. (editor). 1962. Handbook of North American birds. Vol. 1. Loons through flamingos. Yale University Press, New Haven. 567 pp.

Parsons, K.C., and T.L. Master. 2000. Snowy Egret (Egretta thula). In The Birds of North America, No. 489 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. Available http://bna.birds.cornell.edu/bna/species/489/articles/introduction (Accessed October 25, 2007).

Payne, R. B., and C. J. Risley. 1976. Systematics and evolutionary relationships among the herons (Ardeidae). Univ. Michigan Mus. Zool., Misc. Publ. No. 150. 115 pp.

Peters, K.A. and D.L. Otis. 2006. Wading bird resonse to recreational boat traffic: does flushing translate into avoidance? Wildlife Society Bulletin 34(5): 1383-1391.

Powell, G.V.N. 1987. Habitat use by wading birds in a subtropical estuary: implications of hydrography. Auk 104:740-749.

Root, T. 1988. Atlas of wintering North American birds: An analysis of Christmas Bird Count data. University of Chicago Press. 336 pp.

Sibley, D. A. 2000a. The Sibley guide to birds. Alfred A. Knopf, New York.

Spendelow, J. A. and S. R. Patton. 1988. National Atlas of Coastal Waterbird Colonies in the Contiguous United States: 1976-1982. U.S. Fish and Wildlife Service, Biological Report 88(5). x + 326 pp.

Stiles, F. G. and A. F. Skutch. 1989. A guide to the birds of Costa Rica. Cornell University Press, Ithaca, New York, USA. 511 pp.

Stolen, E.D. 2003. The effects of vehicle passage on foraging behavior of wading birds. Waterbirds 26(4): 429-436.

Terres, J. K. 1980. The Audubon Society encyclopedia of North American birds. Alfred A. Knopf, New York.

Traut, A.H. and M.E. Hostetler. 2003. Urban lakes and waterbirds: effects of development on avian behavior. Waterbirds 26(3): 290-302.

Trocki, C.L. and P.W.C. Paton. 2006. Assessing habitat selection by foraging egrets in salt marches at multiple spatial scales. Wetlands 26:307-312.

Links

• Google Images
• NatureServer Explorer
• The Birds of North America

About This Guide

Information for this guide was last updated on: December 10, 2008

Please cite this page as:
New York Natural Heritage Program. 2023. Online Conservation Guide for Egretta thula. Available from: https://guides.nynhp.org/snowy-egret/. Accessed December 8, 2023.