The Olive-sided Flycatcher has a famous song, which is affectionaely transliterated as "Quick! Three Beers!" It's a great piece of bird music, but today we use a common call of the species to elucidate its family tree. The pip-pip-pip call presented here may be heard in the muskegs and mountains from Newfoundland over to Alaska, and thence down to Argentina. Four species make up the super-species of large pewees that sit on high and conspciuous perches and utter this call all afternoon. The northern two species, Olive-sided Flycatcher and Greater Pewee, will also launch into song at any hour. The southern two, Dark Pewee and Smoke-colored, seem to reserve the song for the predawn minutes.
There are other pewees as well. There is the enignmatic Ochraceous Pewee, a member of the large-pewee clade with the ones mentioned above. It lives in the elevational zone above the Dark Pewee in Costa Rica and Panama. Then there is the small-pewee clade, which includes the very familiar Western Wood-Pewee and Eastern Wood-Pewee of the U.S. and Canada, plus several species in the tropics, and representatives on the larger Caribbean islands. They are all in the genus Contopus, and they all belong there. All those so far examined have a common element in their dawn songs. But it's hard to find recordings of dawn song, so mystery remains. I would love to record every one of them, at dawn. That would take me to the islands, to the Chiriqui Highlands, and well into South America.