The cattle egret now outnumbers the combined populations of all other egrets and herons found in North America. No other egret spends as little time near water than does the cattle egret. ( http://www.coos.or.us/~aigrette/ce.htm)
It is sometimes called by names of the animal it associates with, such as Elephant Bird, Rhinoceros Egret, or Hippopotomus Egret.
Three subspecies are recognized: B. i. ibis, B. i. seychellarum, and B. i. coromanda. (Telfair, 1994)
Perception Channels: visual ; tactile ; acoustic ; chemical
The cattle egret is the most plentiful ardeid in many areas of the U.S. Its range continues to expand as a result of widespread landscape conversion to pasturelands, where these birds forage with cattle. (Telfair, 1994)
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Cattle egrets may transmit parasites and other disease organisms to livestock and people, but this is very speculative. Some heronries are considered nuisances when near structures used by humans due to noise, odor, concern over health hazards, and potential danger to aircraft. (Telfair)
Some ranchers rely on cattle egrets for fly control more than they do pesticides.
It has been calculated that an individual cattle egret can obtain up to 50% more food and use only two-thirds as much energy catching it by associating with cattle, as well as with other large ungulate species. Thus it is a very opportunistic and non-competitive feeder. It commonly associates with livestock, wild buffalo, rhino, elephant, hippo, zebra, giraffe, eland, and waterbuck. Due to their practice of perching on these animals' backs, cattle egrets are often grouped incorrectly with 'tick-birds.' In Australia, they have also been observed to associate with horses, pigs, sheep, fowls, geese, and kangaroos. In the Carribean they even follow the plough, capturing exposed earthworms. The cattle egret's major prey is active insects which are disturbed by the grazing activities of the cattle egret's host animals. It eats mostly grasshoppers, crickets, spiders, flies, frogs, and noctuid moths. It is a very active forager, usually feeding in loose aggregations of small or large flocks of mixed sex and age, varying from tens to hundreds of individuals. It may forage in smaller groups or singly. When feeding, it usually walks in a steady strut, followed by a short dart forward, and a quick stab. If they prey animal is small, it is immediately swallowed. If it is larger, it may be jabbed or dipped in water a few times, but it is not dismembered. (Telfair, 1994; Hancock and Elliott, 1992)
The cattle egret, due to its great range expansion in association with cattle ranching, has become a true 'cosmopolitan' species. It occurs in North America, generally not in the west or far north; and Eurasia, though usually not in the east. It also inhabits Africa, Australia and parts of South America. Cattle egret are native to Africa and southern Spain. (Hancock and Elliott, 1978)
Biogeographic Regions: nearctic (Introduced ); palearctic (Introduced , Native ); oriental (Introduced ); ethiopian (Introduced , Native ); neotropical (Introduced ); australian (Introduced ); oceanic islands (Introduced )
Other Geographic Terms: cosmopolitan
The cattle egret is the most terrestrial heron, being well-adapted to many diverse terrestrial and aquatic habitats. Though it does not depend on aquatic habitats to survive, it does make frequent use of them, even when they are not close to livestock-grazing areas. It is also well-adapted to urban areas. In its breeding range, which is similar to its winter range, it often nests in heronries established by native ardeids. (Telfair, 1994)
Terrestrial Biomes: savanna or grassland ; forest ; rainforest ; scrub forest
Range lifespan
Status: wild: 23 (high) years.
Average lifespan
Status: wild: 204 months.
The cattle egret is a medium sized bird, with a 'hunched' posture, even when it is standing erect. In comparison to other egrets, it is short-legged and thick-necked. The total length of the bird ranges from 46-56 cm, and its wingspan averages 88-96 cm. The basic plumage of the adult of both sexes is pure white, with a dull orange or yellow bill, and dull orange legs. For a brief period of time during the breeding season, however, the plumage of the breeding adults is buffy at the head, neck and back, and the eyes, legs and bill are a vivid red. Because of this coloration, it is sometimes called the Buff-Backed Heron. (Telfair, 1994; Hancock and Elliott, 1978; http://www.coos.or.us/~aigrette/ce.htm; http://www.mbr.nbs.gov/id/htmid/h2001id.html)
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 220 g.
The cattle egret is seasonally monogamous. It pair-bonds, but at the start of the breeding season there can be a temporary group of 1 male and 2 females. Breeding starts when small groups of males establish territories. Soon after this, aggression increases, and they begin to perform various elaborate courtship displays, attracting groups of females. Immediately before pairing, a female will attempt to subdue the displaying male by landing on his back. Eventually, the male will allow one female to remain in his territory, and within a few hours, the pair-bond is secure. The female then follows the male to another site where the nest will be built. Copulation usually also takes place at this second site. There is little display involved with copulation. Some rapes and rape attempts have been documented. (Telfair, 1994)
Cattle egrets nest is large colonies with other wading birds. Pairs sometimes reuse old nests, or build new ones with live or dead vegetation. They will build in any place that can support a nest. Both sexes participate in nest-building: the female usually builds with materials brought by the male. They often steal sticks and other materials from neighbors' unattended nests. Material is continuously added to the bulky nests during incubation and after hatching. Throughout mating, nesting, and incubation, a Greeting Ceremony is given whenever one mate returns to the nest to join the other. The Greeting Ceremony involves erection of the back plumes, and flattening of the crest feathers. Eggs are laid every 2 days, and the female does not become attentive to the nest until the last egg is laid. The eggs are light sky blue, turning lighter as time passes. Clutch size is usually 3-4 eggs, although extremes of 1 and 9 have been recorded. Incubation is carried out by both sexes, and lasts 24 days. During the first week, nestlings are easily overheated, and so the parents shade them from the sun beneath their wings. Both parents brood constantly for the first 10 days. The parents may accept chicks from other broods only if they are less than 14 days old. Begging for food becomes very aggressive in days 4-8, and the nestlings are very competative with one another. Siblicide is uncommon, though sibling aggression is strong. Most of the chicks' growth is completed in the nest, but by 14-21 days, the chicks are capable of leaving the nest and climbing in vegetation, and are thus referred to as 'branchers.' At this stage, they remain nearby and continue to beg for food. At 45 days, they are independent, at 50 days they can make short flights, and at around 60 days, they fly to foraging areas. (Telfair, 1994; http://www.coos.or.us/~aigrette/ce.htm)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 22 days.
Average eggs per season: 3.
