The cattle egret (Bubulcus ibis) is a relatively small white heron that can be found inhabiting fields and grasslands in close proximity to cattle. This species has a mutually beneficial relationship with domestic cattle and other large grazing animals, feeding on insects and other small prey that are flushed out by the movement of herds. The association with cattle gives the cattle egret its common name, but this bird has also been called the cow egret or cow bird due to this habit.
Physical Description
The cattle egret is a stocky heron with a short neck, short thick bill, and short legs in comparison to other heron species. Its plumage is all white, with buff-colored plumes during breeding season. The legs and facial skin are yellow in color. It has red eyes and a yellow bill.
Mature cattle egrets reach about 17-22 inches in height and weigh approximately 1 pound. Their wingspan is around 32-37 inches wide. Males and females have similar plumage but males are slightly larger. Juvenile cattle egrets have duller blackish-gray bills and grayish legs.
Habitat and Range
Cattle egrets can be found in open and partially open habitats such as pastures, fields, grasslands, wet meadows, marshes, and the edges of lakes and rivers. They are commonly seen following herds of cattle or other livestock. Originally native to parts of Africa, southern Spain and Portugal, the Middle East, and the Indian subcontinent, cattle egrets have expanded their range dramatically over the past century.
They were introduced to the Americas in the late 1800s and can now be found across most of North America, Central America, and South America. Cattle egrets have also been introduced to Australia and many oceanic islands. They continue to extend their range through migrations and accidental introductions.
Behavior and Diet
The cattle egret has a symbiotic relationship with domestic cattle and other large animals. It feeds on the small prey disturbed by the movement of grazing herds, including insects, spiders, ticks, frogs, mammals, birds, and reptiles. Cattle egrets follow herds or wait for them at regular watering and resting areas. This provides the birds with a steady supply of food. The animals benefit by having insects flushed out and removed. Sometimes the egrets will also ride on the backs of the animals to stay close to the action.
Cattle egrets are highly social and usually feed and roost in flocks. They will often forage with other herons, ibises, storks, and ducks as well. They mainly use visual cues to locate prey while walking slowly through shallow water or grass. They will also stir up vegetation with their feet.
Migration
Cattle egrets are partially migratory depending on their breeding range. Northern populations migrate south to warmer climates during the winter months. Some southern breeding populations are mostly non-migratory. Migratory cattle egrets form large flocks that travel to find favorable habitat and food sources.
Reproduction and Lifespan
Cattle egrets breed in colonies called heronries which provide safety from predators. They build nests in trees near water, making platform nests of sticks lined with vegetation. The female lays between 1-5 eggs which incubate for around 21 days. Both parents feed the chicks by regurgitating food. Young cattle egrets become independent in about a month.
These birds can begin breeding after their first year. They may raise two broods per mating season. Cattle egrets in the wild have an average lifespan of about 15 years. Some exceptional birds have lived past 20 years old.
Relationship with Humans
Cattle egrets are very common near human habitation and are generally not threatened by limited human disturbance. Their association with livestock has allowed them to widely expand their range by utilizing pasturelands. Cattle egrets provide beneficial insect control services around cattle.
They are protected under the Migratory Bird Treaty Act in the United States and parts of their range. Globally they are listed as a species of Least Concern by the IUCN due to their large and growing population numbers. Outside of their native range, cattle egrets are sometimes considered an invasive species as they compete with local wading birds.
Interesting Facts
- The cattle egret’s diet shifts depending on the season – more insects are eaten during breeding season and more amphibians and reptiles during migration.
- The oldest known cattle egret lived to 22 years and 11 months old according to longevity records.
- Cattle egrets have expanded their range by flying to new suitable habitats, but have also crossed oceans by riding on ships and rafts.
- These birds swallow their prey whole. To help digest their food, they ingest grit and small stones which act as a grinding material in their gizzard.
- Cattle egrets exhibit crouching and wing-spreading displays for courtship and communication within flocks.
- The cattle egret’s name refers to its association with cattle, but it also follows other large animals including elephants, rhinos, and zebras.
- These birds consume ticks and can help reduce the spread of tick-borne diseases between cattle.
Conclusion
In summary, the cattle egret is a small heron uniquely adapted to following herds of large animals and feeding on the prey they flush out. This allows them to thrive in grasslands and livestock pastures in close association with humans. Cattle egrets provide insect control services while benefiting from the constant supply of food sources surrounding cattle. Their devoted partnership with livestock has enabled cattle egrets to rapidly expand their range across continents. Despite being an introduced species in some regions, cattle egrets have integrated well into both natural and agricultural environments.