英文關鍵字
active
anas
animals
beauty
behavior
biology
birds
bobbing
canada
colorful
colors
dabbling
duck
ducks
ecology
environment
fauna
female
fertile
lake
male
mallard
mating
nature
normal
ornithology
outdoor
platyrhynchos
reproducing
reproduction
science
season
social
spring
springtime
swimming
three
waterfowl
wildlife
zoology