By Marcia Bonta A N ICY CRUST covered the snow for most of last February, which brought out the highest number of common feeder birds I remember seeing since moving to our home in 1971. One snowy day, seven northern cardinals flew in together at dawn to feed. Later that morning, eight cardinals joined three song sparrows, four American tree sparrows, and too many dark-eyed juncos and white-throated sparrows to count - dozens of them. In mid-afternoon, the snow turned to freezing rain and sleet. The little birds twittered loudly when I spread another pound of mixed seeds before them. The rest then descended like proverbial locusts - a dark, moving blanket covering the white, slick surface. Seeing so many common bird spe- cies on the ground seemed a sign to me that at least our backyard birds were thriving. An article by Elizabeth Pennisi titled "Billions of North American Birds Have Vanished" appeared in Science magazine in September 2019. The piece was based on a comprehensive study of 529 North American bird species from 1970 to 2018. The study led by Kenneth V. Rosenberg of the Cornell Laboratory of Ornithology included 11 scientists from seven institutions. And the results were so startling and unexpected that many news outlets picked up the story. The study revealed 3 billion birds - almost one-third of North America's d isappearing Birds Once they're gone, they're gone FEBRUARY 2020 61