Two Oak Park brothers spied the green and white bird last week during a routine bird-watching trip to Douglas Park. The teens posted photographs on Facebook on the Illinois Birders' Forum, the Chicago Tribune reported Sunday, and other bird-watchers quickly weighed in to confirm the boys' suspicions.
"You're finding something that shouldn't be there," said Ethan Gyllenhaal, 16. "It's so weird to think that it flew 7,000 miles away. You just happen to be looking at the right tree and the right time."
"It's kind like being a proud parent," said Aaron Gyllenhaal, 15.
The elaenia -- about 13.5 to 15 centimeters long and weighing about half an ounce -- is normally found in the forest edges in the Andes Mountains, the Cornell Lab of Ornithology said.
The American Birding Association has not confirmed the bird is, in fact, a white-crested elaenia. No one seems to know how or why the bird traveled 7,000 miles to perch in Douglas Park, the Tribune said.