Cattle Egrets breed in coastal barrier islands, marshes, reservoirs, lakes, quarries, swamps, riverside woodlands, and upland forests. They usually nest in colonies already established by native herons and egrets, and forage in fields with grazing livestock. During spring and fall migration they stop along marine shorelines as well as in farm fields. Some spend winters in the southern United States, mainly in coastal areas where the temperature rarely falls below 40° Fahrenheit. Scattered individuals spend mild winters farther north on both coasts, as far as Washington and Rhode Island. Their North American range is still expanding.Back to top
Cattle Egrets have broad, adaptable diets: primarily insects, plus other invertebrates, fish, frogs, mammals, and birds. They feed voraciously alone or in loose flocks of up to hundreds. Foraging mostly on insects disturbed by grazing cattle or other livestock, they also glean prey from wetlands or the edges of fields that have been disturbed by fire, tractors, or mowing machinery. Grasshoppers and crickets are the biggest item on their menu, which also includes horse flies, owlet moths and their larvae, cicadas, wolf spiders, ticks, earthworms, crayfish, millipedes, centipedes, fish, frogs, mice, songbirds, eggs, and nestlings.Back to top
The male selects a nest site, which is usually in the top outer branches of a medium to tall tree or shrub in a swamp, marsh, or upland.
Both sexes build the nest, but the female does most of the construction with materials brought by the male. The nest is a shallow, untidy bowl with a foundation of robust sticks, an upper layer of smaller twigs or vines, and sometimes a lining of soft plant materials. It measures about 7–24 inches across and 2–12 inches deep.
|Clutch Size:||2-4 eggs|
|Egg Length:||1.4-2.0 in (3.5-5.2 cm)|
|Egg Width:||1.1-1.4 in (2.8-3.6 cm)|
|Incubation Period:||22-28 days|
|Nestling Period:||14-21 days|
|Egg Description:||Pale sky blue to sea green.|
|Condition at Hatching:||Mostly helpless, with dark bluish or greenish skin partly covered with down.|
The most gregarious of all herons, Cattle Egrets flock all year long and form dense breeding colonies and nonbreeding roosts. Cattle Egrets leave their roost or nesting colony just after sunrise, feed in the morning and afternoon with a rest at midday, and make their return flight an hour before sunset. They fly with their necks folded in an S-shape, and run or walk with a swaying gait while foraging. Each breeding male defends a display territory, and the breeding pairs later defend a nest territory at the same or a different site. They are usually monogamous within each breeding season, with occasional trios of two females and one male. In elaborate courtship displays, the males spread their wings, fan their plumes, and prance from foot to foot. Nest predators include grackles, crows, owls, Cooper’s Hawks, Black-crowned Night-Herons, and fire ants. Fledgling, juvenile, and adult Cattle Egrets may be hunted by Peregrine Falcons, Great Horned Owls, Barred Owls, raccoons, red foxes, and domestic dogs.Back to top
Cattle Egret populations declined by 50% between 1966 and 2015, according to the North American Breeding Bird Survey. There is little information on population numbers, but a 2002 study by the North American Waterbird Conservation Plan estimated 1.16 million breeding birds in Texas. The species rates a 7 out of 20 on the Continental Concern Score. Cattle Egret is not on the 2016 State of North America's Birds' Watch List. These birds are native to Africa and Asia, and began expanding worldwide in the 1800s, reaching North America in the early 1950s. Cattle Egret are now established in parts of southern and eastern U.S., and their range is still slowly expanding. Their rapid spread stems from versatile feeding and breeding abilities, an aptitude for dispersing to new areas, and a changing landscape: they gained foraging habitat as people converted land for livestock production and crops. Cattle Egrets may benefit the livestock industry by eating flies (and on rare occasions, ticks) from the bodies of cattle. They are sometimes seen as a nuisance because their colonies can be large, noisy, smelly, and close to populated areas. They are sensitive to pollution in water supplies and agricultural fields. They accumulate residues of some contaminants in their feathers, leading some researchers to suggest they are a useful species for monitoring levels of environmental pollutants.Back to top
Lutmerding, J. A. and A. S. Love. Longevity records of North American birds. Version 2015.2. Patuxent Wildlife Research Center, Bird Banding Laboratory 2015.
Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski, Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link (2017). The North American Breeding Bird Survey, Results and Analysis 1966–2015. Version 2.07.2017. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
Sibley, D. A. (2014). The Sibley guide to birds, second edition. Alfred A. Knopf, New York, USA.
Telfair II, Raymond C. 2006. Cattle Egret (Bubulcus ibis), version 2.0. In The Birds of North America (P. G. Rodewald, editor). Cornell Lab of Ornithology, Ithaca, New York, USA.