The cattle egret (Bubulcus ibis) is a cosmopolitan species of heron (family Ardeidae) found in the tropics, subtropics, and warm-temperate zones. It is the only member of the monotypic genus Bubulcus, although some authorities regard its two subspecies as full species, the western cattle egret and the eastern cattle egret. Despite the similarities in plumage to the egrets of the genus Egretta, it is more closely related to the herons of Ardea. Originally native to parts of Asia, Africa, and Europe, it has undergone a rapid expansion in its distribution and successfully colonised much of the rest of the world in the last century.
Pairs of crested caracara have been observed chasing cattle egrets in flight, forcing them to the ground, and killing them.
The Cattle Egret occurs throughout temperate and tropical regions of the world (Raffaele and others 1998). It is a common permanent resident species in Puerto Rico (Oberle 2018, Raffaele 1989a) and fairly common in Vieques (Gemmill 2015). It has also been reported in Mona and Desecheo (Ventosa- Febles and others 2005). The species is a relatively recent arrival from Africa from which it colonized South America and the Caribbean, and arrived in Puerto Rico in the late 1940s and early 1950s (Arendt 1988). This species occurs in pastures where livestock are grazing or tractors are cutting grass or plowing (Raffaele and others 1998), grassy roadsides, and landfills (Oberle 2018). The atlas fieldwork yielded a total of 560 records within 305 hexagons or 64 percent of the 479 total hexagons (see map). Of the 305 hexagons where this species was found, breeding met the atlas definition of confirmed in 9 percent (27), while the species was observed in 91 percent (278) of the hexagons but without evidence of breeding (see map). Cattle Egret distribution. The map shows the highest breeding code by hexagon and overlaying the ecological life zones in Puerto Rico. Note: percentages may not total 100 due to rounding. 155Cattle Egret/Garza Ganadera
The Cattle Egret forms large colonies during the breeding season and constructs a bulky nest of twigs in a tree (Raffaele and others 1998). Nests can be found in different habitats or ecosystems including swamps, creeks, lagoons, and even offshore cays (J.A. Salguero- Faría, personal observation 2009). Breeding season may vary, ranging from January to July, according to previously published reports (Oberle 2018, Raffaele and others 1998). Atlas results show that the Cattle Egret breeding season extends from January to July (see chart). Results show that the Cattle Egret breeds within the subtropical moist forest life zone (67 percent of the hexagons), the subtropical dry forest life zone (26 percent of the hexagons), and the subtropical wet forest life zone (7 percent of the hexagons) (see table and map).
The Cattle Egrets overall population is increasing, and it is listed as a species of least concern by the IUCN (BirdLife International 2019). Locally, this species is not listed in any of the threatened categories of PRDNER and USFWS. In Puerto Rico, the Cattle Egret has a protected habitat in land of 9 percent or 57 km2 of the total area covered by the hexagons where evidence of breeding was found for this species (646 km2).