423 
Mr. R. Swinhoe on Formosan Ornithology. 
bird it is particularly common in the marshes near Amoy, China. 
They are there seen, numbers together, scattered on the tops of 
the reeds and mangroves, each bird standing on a branch, often 
on one leg, with head sunk between the shoulders, the bill only 
moving as on a pivot, and describing a semicircle, as the bird 
extends its vision. They are tame, and not easily disturbed. If 
alarmed by loud cries, they flutter and drop quietly to the roots 
of the reeds. When they are made with difficulty to take wing, 
they never fly far. I have generally found them at Amoy in 
May, but could never ascertain where they bred, though the 
young, in mottled and spotted Bittern-like plumage (A. lepida , 
Horsf.), were common enough a little later in the year. This 
species is very similar to Ardetta minuta of Europe, of which it 
is the representative form in Asia. 
164. Nycticorax griseus (L.). 
I fully expected to find in Formosa the Red-backed Night- 
Heron of the Philippines, but was annoyed to discover that it 
was still our European friend that prevailed. This bird was 
building abundantly in the fine old banyans in the city of Tai- 
wanfoo; and as my hunters shot them without mercy, I had 
opportunities of examining them in all three plumages—the 
spotted first-year, the light grey second-year, and the adult, 
with all manner of transitional stages. The iris is at first 
greenish yellow, gradually changes to brownish straw-yellow in 
the second plumage, and then deepens and changes to the clear 
pink vermilion of the mature bird. The bill of the adult is 
black, with yellowish edges to basal two-thirds of gonys. Lore at 
base of bill grey, greenish near and round the eye. Pupil hori¬ 
zontally ovate, expands in the dark and at death to nearly full 
extent of the eye, which projects much. The legs of immature 
birds are green; in the second plumage they are strongly tinted 
with yellow ochre on the under tarsi and soles, and often more 
or less grey throughout. In the adult they become a uniform 
orange-ochre, the claws always being black. 
In summer, when the young require incessant feeding, it is 
not unusual to meet the Night-Heron abroad during the day, 
searching for food; but at other seasons it is strictly a night-bird. 
