— another sign that we're in the middle of a 6th mass extinction

"There are 2.9 billion (yes, that's billion with a B) fewer birds on the North American continent today than there were 50 years ago.
In a study published today in the journal Science, researchers report that hundreds of North American bird populations — from songbirds like meadowlarks to backyard favorites like sparrows — are thinning. Overall, the analysis suggests, we've seen a 29% decline.
"We expected to see continuing declines of threatened species. But for the first time, the results also showed pervasive losses among common birds across all habitats, including backyard birds," Kenneth Rosenberg, the lead author of the study, said in a press release."