原始鸟类在美洲地区是怎么样的呢?Scientists studying ancient species migration believe northern birds had the ability to colonize continents that southern species lacked.The research,published in Ecography,reveals how the ancient“land bridge”of Panama,which first connected North and South America,caused an uneven species migration,leading to a new understanding of species diversity today. Scientists studying ancient species migration believe northern birds had the ability to colonize continents that southern species lacked the research, published in Ecography, reveals how the ancient “land bridge ” of Panama , which first connected North and South America, caused an uneven species migration, leading to a new understanding of species diversity today.