The female Lawrence’s goldfinch is gray like a nonbreeding adult female American, but note the American’s wider, buffier wing bars and different pattern of white in tail. The call notes of the ...

A female's gestation period lasts 285 to 300 days, after which she gives birth to one calf (or, rarely, two), which is weaned after five or six months. LIFE CYCLE: Bison reach sexual maturity at two ...

Both the male and female American robin are gray-brown birds with yellow bills and reddish-orange breasts, but the male’s ...