Photo by R. C. Tweit
Ardea alba
Great Egrets were decimated in the late 1800s by plume hunters who sought the delicate long breeding plumes on the bird’s back known in the millinery trade as “long whites” in contrast to “short whites” or “cross aigrettes” in reference to the short, recurved plumes of the Snowy Egret (E. thula). These feathers were in great demand for women’s hats. In Texas, the sale of feathers was an extensive business from about 1869 until 1907 with reports of this activity from coastal areas (Eagle Lake in Colorado County and Corpus Christi in Nueces County) and from inland areas along the Neches, Angelina, Sabine, and Trinity rivers (Casto 1983). After receiving legal protection and as the result of conservation and management efforts, both species have recovered and are wide-spread.
In Texas, an important influence on waterbird populations is the 20-25 year precipitation cycle (Telfair 2002). Between the early 1960s and late 1980s, there was a significant upward trend in the cycle; since then, the trend has begun to decrease\ (Tom Spencer, Texas Forest Service, pers. comm.). The trend varies regionally and there are intermittent drought years and irregular intervals with pronounced wet/dry springs-summers such as those associated with El Niño/La Niña years and massive slow-moving atmospheric disturbances (Dr. Robert. K. Peters, NWS Observer for Tyler, Texas, pers. comm.). Inland wetland habitats are particularly subject to the effects of these trends. Unfortunately, there is a lack of data about the status of Great Egret populations in Texas before the 1970s; so, the possible relationship between these breeding populations of this species and the precipitation cycle are unknown for earlier years.
The large size and relatively small number of Great Egrets per colony probably insure that census data are fairly accurate compared to the smaller yet much more numerous species with which they nest.
DISTRIBUTION: Great Egrets inhabit a variety of marine and freshwater habitats associated with mud flats, freshwater and salt marshes, seashores, lagoons, river and creek margins, ponds, oxbow lakes, swamps, damp meadows, and human-made habitats, e.g., ditches, canals, flooded rice fields, and aquaculture ponds (Kushlan and Hancock 2005). Most breeding occurs east of the 98th meridian in the eastern wooded area of Texas. Some breeding colonies have also been recorded in north central Texas and the Rio Grande Valley (TBBA). Sporadic nesting is recorded in Midland County between the South Plains and West Edwards Plateau (TBBA) and in the Trans-Pecos region at El Paso in El Paso County (Lasley and Sexton 1994) and McNary Reservoir in Hudspeth County (Peterson and Zimmer 1998). Based upon Texas colonial waterbird censuses (1973-1990), most of the breeding population is coastal (45-87%).
SEASONAL OCCURRENCE: Great Egrets breed from early March to early August (eggs have been found from March 20–June 23 and nestlings from May 19-August 4 (Oberholser 1974). Great Egrets are common residents along the Coastal Prairies and are locally common summer residents in the eastern and central areas of the state, north to Oklahoma. They are uncommon year-round visitors to the Trans-Pecos. Large post-breeding flocks may occur in late summer and early fall, both inland and along the coast; and in winter, individuals are rare to uncommon and irregular visitors northward to the South Plains (Lockwood and Freeman 2004). However, in recent years, some individuals overwinter inland in central and eastern Texas irregularly northward to the Dallas-Fort Worth area where they are becoming more common (Texas Ornithol. Soc. 1995).
BREEDING HABITAT: Great Egrets may nest in single pairs or in large mixed-species colonies. Nest sites are mostly in trees and shrubs, often near the highest points in multi-species colonies; occasionally nests are found on the ground or on artificial nest platforms (McCrimmon et al. 2001). Sites may or may not be over water as well as on islands. Sites may include oxbow lakes, ponds, marshes, estuaries, reservoirs, and on islands in reservoirs, and natural and dredge-material (spoil) islands (McCrimmon et al. 2001). Some large multi-species colonies are reestablished annually for as many as 30+ years, but others are not; reasons for this difference are unknown. Some of the large colonies are considered nuisances when they are located near human habitation (Telfair et al. 2000).
STATUS: According to Texas colonial waterbird censuses from 1973-1990, the breeding population of the Great Egret fluctuated between 2,445 and 12,332 pairs. These data also reveal an annual increasing trend of 3.8%. Unfortunately, comprehensive inland annual breeding censuses have not been conducted since 1990. However, coastal data between 1973-2000 were analyzed by McFarlane (2002). He found an annual decreasing trend of -1.6%. Nevertheless, within these time spans, there were years with high census numbers; so, the decline may be related to regional responses to the precipitation cycle (see Introduction and Distribution discussions above). North American Breeding Bird Survey (BBS) data for Texas (Sauer et al. 2005) give annual trends of -5.6% (1966-1979), 2.6% (1980-2005), and 0.3% (1966-2005); thus, supporting the statewide increasing trend indicated by colonial waterbird census data. However, the BBS data for the Coastal Prairies (in agreement with the analysis of MacFarlane [2002]) indicate a decreasing trend: -9.6% (1966-1979), -2.6% (1980-2005), and -4.3% (1966-2005) as reported by Sauer et al. (2005).
Text by Raymond C. Telfair II (2007)
Literature cited:
Casto, S. D. 1983. The market hunting of Texas birds. Bull. Texas Ornithol. Soc. 16: 2-15.
Kushlan, J. A. and J. A. Hancock. 2005. The herons. Oxford University Press Inc., New York.Lasley, G. W. and C. Sexton. 1994. Texas region (summer season). Am. Birds 48: 960-964.
Lockwood, M. W. and B. Freeman. 2004. The TOS handbook of Texas birds. Texas A&M. University Press, College Station
McCrimmon, D. A., Jr., J. C. Ogden, and G. T. Bancroft. 2001. Great Egret (Ardea alba). In The Birds of North America, No. 570 (A. Poole and F. Gill, eds). The Birds of North America, Inc., Philadelphia, PA.
McFarlane, R. W. 2002. Texas colonial waterbird trends (Powerpoint presentation). http://www.fws.gov/texascoastalprogram/TCWC.htm
Oberholser, H. C. 1974. The bird life of Texas. University of Texas Press, Austin.
Peterson, J. J. and B. R. Zimmer. 1998. Birds of the Trans-Pecos. University of Texas Press, Austin.
Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, results/analysis 1966-2005. Version 6.2.2006. USGS Patuxent Wildl. Res. Cnt. Laurel, Maryland. http://www.mbr-pwr.usgs.gov/bbs/bbs.html
Telfair, R. C. II. 2002. Inland heronries in Texas. Texas Partners in Flight Newsletter, Texas Parks and Wildl. Dept. 9: 20.
Telfair, R. C. II, B. C. Thompson, and L. Tschirhart. 2000. Nuisance heronries in Texas: characteristics and management. 2nd ed. Wildl. Diversity Prog. , Wildl. Div., Texas Parks and Wildl. Dept. PWD BK W7000-134 (1/00).
Texas Ornithological Society. 1995. Checklist of the birds of Texas. 3rd edition. Printed by Capital Printing, Inc. Austin, Texas.