I’ve had less luck with photographing spring Blackpolls, in my yard or elsewhere. These are from Ohio’s Magee Marsh this past spring, and are my best shots thus far.
Hard to imagine confusing these two, right? But as the title photo shows, fall feathers change significantly from spring. The Blackpoll makes the most dramatic transformation, losing its striking black and white, and sometimes gaining a yellowish/greenish cast. The Bay-breasted loses its dark brownish red, so its olive green color becomes more dominant. That leaves two similarly sized warblers, with strong wingbars, weak eyelines and eyerings, varying degrees of streaking, white tipped primaries and tertials, and a yellow-green-buff overall look.
My main source for this DC and everyday warbling is The Warbler Guide by Tom Stephenson and Scott Whittle, also available at Cornell Lab. This Wisconsin eBird article is also helpful and notes the “Baypoll” moniker birders may use when flummoxed. I made this chart of the basic differences in fall plumage. Remember, these are typical markings, and not every bird checks each box. Hopefully the formatting will hold when published.
Eyeline short, fine eyeline; faint eyebrow longer, wider, more distinct eyeline
Eyering may have faint, broken eyering broken eyering
upper beak mostly dark mostly dark
lower beak pale, base may be pinkish pale, no pink
Breast unstreaked olive yellowish wash with streaking
Flank often a buffy or reddish wash usually light grayish streaking
Belly unstreaked, buffy faint streaks, may be yellowish
Undertail often has light buffy wash white, contrasts w/ yellowish breast
Tail short; black edges & tip underneath short; grayish edges & tip underneath
Wingbars thick wingbars, strong black in between thin, sharp wingbars, less strong black
Tertials broad white edges contrasting white edges
Primaries white tipped white tipped
Back yellow-green, always streaking olive green, usually black streaking
Legs pale or dark legs often orangish, but can be dark
Feet dark feet pale orange feet
Movement large and slow for a warbler slow moving
I’ll go down this chart to illustrate the distinctions I have photos for and I’m fairly confident in the ID. Bay-breasted photos are aligned left and Blackpoll right. As always, I welcome corrections and clarifications.
I hope I haven’t confused an already confusing identification challenge. I’ll repeat that I welcome corrections and any additional clarifications.
Now it’s your turn to put all this to use in a challenge. This tiny ball of cuteness was one that had me stumped for some time. Any guesses as to Bay-breasted, Blackpoll, or do you give up and call it a Baypoll? I have my guess, but I could be wrong.
What’s going on in your birdy world?