The largest species of loon, this bird sports a light yellow bill — thus the name — with striking white spots on a black background. During the non-breeding season, it's much less noticeable because it molts to a light brown color.
"They're eye-catchingly beautiful,” Senner said. “They are also incredible vocalists, with their songs and displays often audible for miles around."
While they're nesting in the summer, yellow-billed loons are quite vocal. Their calls can sound like laughing or yodeling during the day and like crying at night. During the winter, however, the birds don't make a lot of noise.
They mostly migrate to Asia, with recent research showing many Alaskan nesting yellow-billed loons spending the winter off the coast of Japan, Senner said.