In the boreal, they are also the home where almost 50 percent of the 800 bird species found in North America migrate north to breed and raise their young.
亜寒帯はまた 北米で見られる800種類の鳥類の 約半数の鳥たちの生息地でもあり 亜寒帯に渡って産卵し 子育てをします