Ardea virescens var. amurensis Schrenck, Reis. Amurl. (1860),
1, 437.
Butorides amurensis Sharpe, Cat. Birds Brit. Mus. (1898), 26,
181; Hand-List (1899), 1, 200; McGregor and Worcester, Hand-List
(1906), 34.
Calayan (McGregor); Cebu (Everett, McGregor); Luzon (Whitehead);
Palawan (Everett); Samar (Steere). Greater Sunda Islands, China,
Japan, Celebes, Amurland.
Although in color this species seems to be exactly like B. javanica it
is much larger; the length of wing is particularly noticeable and the
bill is longer, and deeper. A male collected by Major Mearns measures:
Wing, 210; tail, 73; culmen from frontal feathers, 66; depth of bill at
posterior border of nostril, 15; tarsus, 54; middle toe with claw, 62.
A female from Calayan measures: Wing, 197; tail, 69; culmen from
frontal feathers, 64; depth of bill at posterior border of nostril,
13; tarsus, 52; middle toe with claw, 54.
Some of the records for B. javanica probably refer to the present
species but it is impossible to disentangle them.