Pelecaniformes / Ardeidae / Butorides
Little Heron
Butorides atricapilla · 绿鹭
Introduction
A small heron, typically 44 cm in length, occurring across the Old World tropics. Twenty recognized subspecies are distributed from sub-Saharan Africa through the Middle East, South Asia, Southeast Asia, and East Asia to Australia and the Pacific islands. Inhabits mangrove swamps and the vegetated margins of rivers, streams, lakes, and coastal lagoons, utilizing both freshwater and marine environments. Sedentary, though some populations make local movements. The species was recently split from the striated heron (Butorides virescens) of the Americas based on genetic evidence.
Description
A small, compact heron measuring 35–48 cm in length with a wingspan of 52–60 cm. Adults weigh 130–250 g and the sexes are similar in appearance. The plumage is highly variable across its range, even within populations. Classic adult plumage features a blue-grey back and wings, white underparts, a dark black cap, a distinctive dark line extending from the base of the bill to below the eye, and relatively short yellow legs. Juveniles are browner above with streaking on the underparts. Two Australian subspecies exhibit dimorphism, occurring in both grey and rufous color morphs.
Distribution & Habitat
Occurs throughout the Old World tropics from sub-Saharan Africa eastward through the Middle East, Indian subcontinent, Southeast Asia, and East Asia to Japan, Australia, and the Pacific islands. Inhabits a variety of wetland habitats including mangroves, freshwater marshes, riverbanks, lake margins, and coastal lagoons. Primarily sedentary throughout its range, though some populations may make local movements in response to water conditions or food availability.
Behavior & Ecology
Forages by standing motionless at the water's edge, waiting to ambush prey with a rapid strike. The diet consists primarily of small fish, frogs, and aquatic insects. Nests are constructed hidden amongst shrubs or overhanging branches near water. The clutch contains 2–5 eggs, incubated for 19–25 days. Chicks are covered in pale-grey down with white coloring on the upperparts and fledge at approximately 5 weeks of age.
Conservation
The species has a very large range and is considered common in many areas. While specific population estimates are not available, the species appears stable across most of its extensive range and is not considered to face significant conservation threats at the global level.
Source: Wikipedia · CC BY-SA 3.0
