Field guides are wary about the difference between the song of the Red-eyed Vireo and the song of the Philadelphia Vireo.
“The song of the Philadelphia Vireo is very similar to the song of the Red-eyed Vireo but tends to be higher pitched, slower and with longer pauses between phrases. Identification by song is risky” (Birds of Ontario)
“The song of the Philadelphia Vireo is very similar to the song of the Red-eyed Vireo but, on average is weaker and choppier, with longer phrases averaging one phrase every three seconds (but the Red-eyed can match these characteristics).” (Sibley Birds)
I tend to identify all as Red-eyed Vireos unless I see the individual and it is a Philadelphia Vireo.
I have seen Philadelphia Vireos on past Terrace Bay (north of Lake Superior) surveys so listen very carefully to each vireo we encounter. I have brought along a phone with the Merlin Bird Call App for this trip. Generally it is quite accurate though did identify baahing sheep as a Warbling Vireo, a Raven as a Crow and frequently adds Yellow Warbler when none is present. When we suspected a Philadelphia Vireo this morning, I turned on the app which indicated that the singer was a Philadelphia Vireo. Great – but the next time the bird sang, the app indicated a Red-eyed Vireo. Sigh…
Terrace Bay survey views:
I have used more of your photos for my art classes. I am so glad you said you didn’t mind.
In the great gardens, after bright spring rain,
We find sweet innocence come once again,
White periwinkles, little pensionnaires
With muslin gowns and shy and candid airs. – Dame Edith Sitwell (1887–1964)