Bird populations in the United States and Canada have dropped by 29% since 1970, signifying 2.9 billion birds lost in almost 50 years, according to a new study.
원문출처 : https://www.cnn.com/2019/09/19/world/north-america-bird-population-loss-scn/index.html
원문출처 : https://www.cnn.com/2019/09/19/world/north-america-bird-population-loss-scn/index.html