Featured Species: Cattle Egret (Bubulcus ibis)

In July 2016 we returned to one of the most famous Cattle Egrets (Bubulcus ibis) nesting colonies in Panama. It is easily accessed since the road to Darien passes right beside the spot, located about one hour from Panama city before the town of Chepo. This is a wetland in a cattle farm that during the rainy season gets flooded, and becomes the nesting place for several species and not just the egrets.

We were able to witness the nesting of other species such as Anhinga (Anhinga anhinga), Pied Water-Tyrant (Fluvicola pica), Watlled Jacana (Jacana jacana), and Rusty-margined Flycatcher (Myiozetetes cayanensis).

Anhinga (Anhinga anhinga) - male and juveniles

Pied Water-Tyrant (Fluvicola pica)

Anhinga (Anhinga anhinga) - male

Cattle Egret (Bubulcus ibis) - breeding plumage

Adult Cattle Egrets are all white with a yellow bill and legs. In breeding plumage they have golden plumes on their head, chest, and back. The short, thick-necked Cattle Egret spends most of its time in fields rather than streams. It forages at the feet of grazing cattle, head bobbing with each step, or rides on their backs to pick at ticks. It was originally native to parts of Southern Spain and Portugal, tropical and subtropical Africa and humid tropical and subtropical Asia. In the end of the 19th century it began expanding its range into southern Africa, and were first sighted in the Americas on the boundary of Guiana and Suriname in 1877, having apparently flown across the Atlantic Ocean. It was not until the 1930s that the species is thought to have become established in that area and quickly spread across the continent.

Cattle Egret (Bubulcus ibis) - breeding plumage and pairing coloration

During the breeding season the bill, legs and irises become bright red for a brief period prior to pairing. The massive and rapid expansion of the cattle egret's range is due to its relationship with humans and their domesticated animals. Originally adapted to a commensal relationship with large grazing and browsing animals (including camels, ostriches, and rhinos), it was easily able to switch to domesticated cattle and horses. As the keeping of livestock spread throughout the world, the cattle egret was able to occupy otherwise empty niches. Many populations of cattle egrets are highly migratory and dispersive, and this has helped the species' range expansion.

Cattle Egret (Bubulcus ibis) - with nestlings

Cattle Egret (Bubulcus ibis) - fledgeling

The nest is a small platform of sticks in a tree or shrub constructed by both parents. The clutch size can be anywhere from one to five eggs, although three or four is most common. Incubation lasts around 23 days, with both sexes sharing incubation duties. The chicks become capable of regulating their temperature at 9–12 days and are fully feathered in 13–21 days. They begin to leave the nest and climb around at 2 weeks, fledge at 30 days and become independent at around the 45th day. Juveniles have dark legs and bill.

Cattle Egrets (Bubulcus ibis) - mating

The male displays in a tree in the colony, using a range of ritualised behaviours such as shaking a twig and sky-pointing (raising his bill vertically upwards), and the pair forms over three or four days. A new mate is chosen in each season and when re-nesting following nest failure. Sticks are collected by the male and arranged by the female.