Each year in the continental United States, at least 1.4 billion birds die in the sharp, uncaring fangs of domesticated cats, according to a major study published today in Nature Communications. And that's the conservative estimate — the study shows that the real number of birds killed by cats could be closer to 3.7 billion. The study's authors say these new estimates paint a bleak picture of how cats affect nearby wildlife:

Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals.

In other words: Jonathan Franzen, the American novelist and avid birder, was right all along. Or least protagonist of his most recent novel, Walter Berglund, was. The final chapter of Freedom features a testy dispute, between him and neighborhood mother, over the impact of cats on the bird population of rural Minnesota, so its author ought to feel vindicated about today's new findings: