The Willow Flycatcher (Empidonax traillii) may not be one of North America’s most colorful birds, but for birdwatchers, it presents one of the continent’s classic identification challenges. Small, olive-brown, and subtly marked, it belongs to the notoriously difficult Empidonax group of flycatchers, several of which can look almost identical in the field. Fortunately, the Willow …
