ML639039826

觀察細節

One along the road by the ridge trail sign, one along the sandy beach/beaver dam. Both singing and well seen. Yellow wash on breast. Daintier than red eyed. In the recording the Philadelphia starts at 20 seconds. There is at least one red eyed singing incessantly in the background, but the Philadelphia is louder and closer. Its phrases are more spaced out, and it is more sibilant and reaches a higher pitch. It is visually distinct in the spectrogram. Merlin seemed to ignore this bird and did not ID it as Philadelphia, but I watched this bird singing at fairly close range. edit: several months later I have read this Sibley blog post: https://www.sibleyguides.com/2024/04/distinguishing-philadelphia-and-red-eyed-vireos-by-song-is-it-possible/ It's very interesting that he thinks these species cannot be distinguished reliably by song! I do not doubt this, but also, my experience in finding the handful of philadelphia vireos I have seen in recent years has been that they sounded different in the way I describe above and that's what keyed me into them. This may simply be selection bias though: I hear a weird sounding vireo and I chase it down hoping to find a philly. If it's a red-eyed, I say "I'm just hearing things" move on and forget about it. If it turns out to be a philly, I say "aha! and file the information away". I never even investigate a bird that sounds like the average red-eyed, so I never get contradictory feedback.