Democratic presidential candidate Bernie Sanders smiles as a House Finch lands on his podium during a rally at the Moda Center in Portland, Oregon. Photo: Steve Dykes/AP

Last Friday at a rally in Portland, Oregon, presidential candidate Bernie Sanders received an unexpected visitor while addressing the crowd: A small bird landed on his podium and lingered for nearly half a minute, sparking wild applause and a new campaign meme. “Birdie Sanders” has since gone viral.

Sanders was quick to take advantage of the serendipitous situation by characterizing the bird as a dove asking for world peace. However enticing that symbolism, the bird clearly wasn’t a dove—nor was it a female goldfinch, as indicated in a retweet by Rachel Maddow. Audubon staff quickly sized it up and made the correct ID: Birdie Sanders is a female House Finch.

“Female House Finches are evenly grayish-brown on the face and back and have gray-brown streaks on their belly and sides,” says David Ringer, Chief Network Officer for Audubon and expert birder of the hour. “No other bird in the Portland area really matches that description.”

Though the female House Sparrow looks similar, it lacks streaking on its belly and has a pale line above its eye—a distinguishing feature not apparent in photos of the avian endorser. The female Song Sparrow does exhibit this streaking, but has contrasting facial feathers that struck it from contention. That just leaves the female House Finch, which has a very plain face without contrasting marks.

There was also one more clue to Birdie Sanders’ identity: its whereabouts. House Finches are at home in highly developed human environments—they are, after all, called House Finches for a reason—so it’s not unusual for them to nest inside a building or stadium, such as the Moda Center where the rally was held.

That doesn’t mean the bird was entirely unfazed by the thousands of politically charged Portlandians also in attendance. “With all the noise and commotion, it is possible the bird may have been a little disoriented or startled,” says Ringer. If so, the House Finch didn’t show it. Rather, it seemed to relish its role exemplifying another Internet meme: Sanders, in the home of Portlandia, had just put a bird on it.