More than half a century ago, conservationist Rachel Carson sounded an alarm about human impacts on the natural world with her book Silent Spring. The treatise spawned the modern conservation movement. But research from the Cornell Laboratory of Ornithology and the American Bird Conservancy published in 2019 shows bird populations have continued to plummet in the past five decades, dropping by nearly three billion across North America - -an overall decline of 29 percent from 1970.

That's more than 1 in 4 birds that have disappeared from the North American landscape in a mere half a century.

Certainly avian disease is a problem, but climate change, habitat destruction, and rampant pesticide use together are irrevocably changing our natural world. Because of the roles birds play in ecosystems, the magnitude of the decline could significantly affect the continent's food webs and ecosystems -- pest control, pollination and seed dispersal, etc.