Many of us may have watched, on TV, the scene of an open savanna with cattle egrets pecking at insects near the mouth of a large African buffalo. As a matter of fact, such a scene takes place almost every day on Lantau!

We frequently see herds of buffaloes walk around the marshes in Shui Hau and Pui O, having Eastern Cattle Egrets (Bubulcus coromandus) in tow. The reason behind is that the insects uncovered in soil during the buffaloes’ moves will easily become the feed of the egrets. In the context of ecology, such a relationship between the two organisms is known as “commensalism”, where one (commensal species) benefits from the other (hosts) by means of, say, obtaining food or sheltering, without doing harm to the host. The harmonious partnership between cattle egrets and buffalos has become a rare sight in Hong Kong in recent years.

The Eastern Cattle Egret found in Hong Kong is categorized as two groups, namely resident and migratory populations. During the breeding season between March and August, they are adorned with long rufous plumes on their crowns, backs and lower necks. The scene of cattle egrets living harmoniously with grazing buffaloes in marshes is one of the indispensable features of South Lantau.