two birds fighting
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Who’s the toughest bird? Continentwide ranking reveals a surprise

If lions are king of the savanna, woodpeckers are probably king of your backyard. Or as researchers write this week on bioRxiv, when a fight for food breaks out, “bigger is better, but woodpeckers are best.” Seeking to create a continentwide pecking order of birds in the United States and Canada, the team turned to citizen science. Project FeederWatch, associated with Cornell University’s ornithology lab, is an online database with more than 20,000 users documenting feeder bird behavior right in their backyards. Just as the team expected, birds fall into a ranking system based on body size. (In a fair matchup, two starlings duke it out in image above.) There are a few nuances, however. The researchers confirmed a previously studied “rock-paper-scissor” conflict in some cases when birds are similar in size. For example, when all three species are in the same place, the house finch dominates the purple finch, the purple finch dominates the dark-eyed junco, and the dark-eyed junco dominates the house finch. To their surprise, however, woodpeckers were more dominant than expected given their size, which varies among woodpecker species. So basically if woodpeckers were boxers they’d always dominate their given weight class. (This is probably because—unlike boxers—they can take hard hits to the head without sustaining brain injury.) And although the paper has generated some interesting fantasies about unlikely bird battles on Twitter, the researchers question how biologically meaningful a continentwide hierarchy really is when some birds will never really throw down in nature—for now. Perhaps, the team puts forth, the list will become a handy reference as different species’ ranges shift and encroach on others as the climate changes.