英文關鍵字
achromatic
african
anser
aquatic
bigger
birds
branta
brazil
bremen
brown
cataloged
chinese
classification
coloring
different
ducks
earth
easily
embden
family
features
fur
geese
image
known
lathe
life
long
main
necks
others
peculiar
peculiarity
photography
races
sales
scientific
sevastopol
species
spin
swans
total
toulouse
two
video
water
white
world