For the Birds: Molting adds another layer of confusion to fall birding

Photo by Elena Heiden
A molting eastern towhee seen in Winchester, N.H., summer 2019.

I have written several times about the difficulties of bird identification in the fall. I have noted that males often lose their breeding plumage and look much more dull in the fall. The other day I spotted a male scarlet tanager in an apple tree. It looked nothing like the spectacular red-and-black bird that it looked like in the spring. Rather, it was a dirty yellow overall, but the dark wings gave it away as a tanager.

I have noted that first-year birds are heading south for the first time and haven’t reached adult plumage yet. Also, female birds, which often do not resemble males, are not quite as secretive as they are in the spring and are seen more often this time of year. What I failed to mention, however, is that late summer and early fall is also when many birds are going through a molting process. This only adds to the confusion of the challenging fall migration.

I was reminded of this when a photo came through from Elena of Winchester showing a very oddly plumaged bird. The rusty, or rufous, feathers on its side gave the bird away as an eastern towhee, but otherwise the bird looked nothing like the male or female eastern towhees you would see in a field guide. The markings and colors were totally off on this bird, which is possibly a first-year bird going through its first molt.

No field guide — book or digital form — could possibly picture every bird in every possible plumage. Birds may look different day to day or week to week during the molt. Sometimes you have to rely on other sources and your instincts to get an ID.

When I think of birds molting, I tend to think of two things. Have you ever seen a cardinal with a bald black head? That bird is likely going through a molt and will look more cardinal-like shortly. Perhaps the most extreme example of molting in New England is the male wood duck. In breeding plumage the male wood duck is arguably the most spectacularly plumaged bird in our region. The colors and patterns are eye-popping and it is hard to imagine a more beautiful bird. Male wood ducks, however, drop all those beautiful feathers during the molt and are rendered flightless. During that time they are unspectacularly colored in dull browns and grays. Soon enough, however, the colorful plumage comes back and they are proudly strolling around New England’s ponds again.

So yes, the fall migration is tricky with its first-year birds, non-breeding plumaged males, and molting birds, but don’t let that stop you from enjoying as many bird walks as possible this time of year. Take advantage of the beautiful New England fall weather and get in as many bird walks as you can before winter sets in. (Not that you have to stop taking bird walks in the winter.) If you come across a bird you can’t identify, try to grab a photo of it and send it to me. Or write to me with the description and I will do my best to try to pinpoint the species. If we still can’t figure it out, that’s OK too. You got out there and enjoyed the outdoors and we both exercised our brains a little.

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