The bird population in the United States and Canada has decreased by 29 percent since 1970, according to the findings of a new study released Thursday.
The study, published in the journal Science, found that change means there are 2.9 billion few birds in the sky than five decades ago.
The study was the most in-depth investigation scientists have conducted to determine what is happening to the planet’s birds. Over 500 aviary species were surveyed for the analysis.
David Yarnold, president and chief executive of the National Audubon Society, described the massive drop as “a full-blown crisis,” in a statement Thursday and called for action.