“That bird doesn’t really look goldfinchy,” said a perplexed Bill. “But I can’t tell what it is.” Bill had been keeping watch on the mist net near the back feeders as we swam and splashed in the pool with family members. Normally we just band birds in winter, so this was a trial to see what, if anything, we could discover by summer banding. It had been a good way to learn the looks of young birds and to get some practice at skulling—looking at the development of the skull bone as a way to identify hatch-year birds. Cardinals, Song Sparrows, Titmice, occasional Ruby-Throated Hummingbirds, lots of House Finches (banded and transported as part of our homing research), and Goldfinches had graced our nets and each one but the “hummers” left with a tiny numbered band on one leg.
All birders know the feeling of being able to identify some bird, not by seeing all the specific field marks, but by more of a gestalt–it just looks like that kind of bird. And more often than not, if we chase the bird to get a good look, we find we are right. Male American Goldfinches in their brilliant gold and black breeding plumage are some of the most beautiful and easily identifiable birds.
But this bird in the net, while it was a dazzling yellow and about the right size, just did not look “goldfinchy” to Bill. He left the pool-yard, dripping, to retrieve our puzzle.
“So what is it?” I asked when he had the bird in hand. “I don’t know!” This was not the answer I expected. Bill doesn’t know what it is??? I made a towel-wrapped dash through the house to get Peterson’s Warblers and Sibley’s. We had to ID the bird correctly before Bill could band it.
We turned page after warbler page in Sibley’s looking for a warbler-sized bird with plain yellow on the belly from beak to the tip of the tail and a darker “greenish” color on top from the bill to the tip of the tail.
The flight feathers of the wings and the tail feathers had multiple colors: pale black, yellow and “greenish”.
It was strikingly colorful and plain at the same time. Looking back and forth between several possibilities, we finally made a preliminary identification as a female Yellow Warbler although we could not see even faint rusty streaks on the breast.
Then I remembered—under-tail coverts! Looking at the color of feathers that cover the base of the tail on the underside of a bird and looking at the color, pattern and shape of tail feathers is one way to differentiate warbler species. And the Peterson Warblers guide has two pages showing all of the possibilities.
Scanning the 52 tail and covert feather options, it was clear that our preliminary identification was, indeed, correct. There wasn’t anything else with undertail coverts that looked like the bird in Bill’s hand.
So we formally said “Hello” to our female Yellow Warbler—the first Yellow Warbler ever banded on our property, in fact, the first Yellow Warbler Bill or I had ever held or banded.
She got her tiny band, posed for some photos and soon was on her way. And as she departed, she left us a little something which, thankfully, landed just outside the edge of the pool.