Today’s column is inspired by a common mistake involving a common grackle.
Last week, my article about the earliest birds of spring ran with a photo labeled as a common grackle. It wasn’t. The image was actually a great-tailed grackle I had submitted with a different column ten years ago.
This is a perfect example of what makes bird identification look harder than it really is. The truth is, most bird IDs are easy. There are just a few traps that make them seem difficult.
One of the biggest challenges is plumage variation. Males and females often look different from each other. Fledglings look different from their parents. Birds sporting bright spring colors can look very different in their duller autumn plumage.
Many birds are also very good at hiding. Lots of soras and Virginia rails will arrive in April, but how many people will actually see one well enough for a positive identification? These freshwater marsh species skulk in the reeds.
Some birds make identification difficult by wandering. It’s naturally harder to recognize a bird you’ve never seen before, or even suspected could be there.
Perhaps the biggest challenge is presented by species that look very similar. Hence this Tale of the Tails.
Grackles are blackbirds. We have three species in North America — common, boat-tailed and great-tailed. They closely resemble each other, although there is some geographic separation between them.
Common grackles are, uh, common. They span much of the continent, from the Atlantic to the Rocky Mountains. They are the smallest of the three and the only one that nests in Maine.
Boat-tailed grackles are slightly larger than common grackles. They are found all along the Atlantic coastline. They seldom move inland and rarely visit north of Connecticut.
Great-tailed grackles are mostly western birds, seldom seen east of the Mississippi River. They are significantly larger than the other two, with a longer tail that justifies their name.
Common and boat-tailed grackles overlap along the Atlantic coastline. To be honest, they are similar enough to make me look twice whenever I am within that overlap zone.
If you think grackles are hard, try another pair of nearly identical twins. Male rusty blackbirds in the eastern United States look very similar to Brewer’s blackbirds in the West, and the two overlap broadly across the middle of the country. We don’t see Brewer’s blackbirds in Maine, and our rusty blackbirds quickly disappear into the northern forest during nesting season. As a result, most area birders have never had the opportunity to separate the two by sight.
Terns can also present an identification headache. Four species of midsize terns can show up in Maine, and three of them nest here. It would take an entire column to describe how to tell them apart.
Long-billed dowitchers have long bills. But so do short-billed dowitchers. Many of our small sandpipers resemble each other. We rarely see sedge wrens in Maine, and that’s probably a blessing. They are almost indistinguishable from marsh wrens, which nest here in abundance.
As reported in the Bangor Daily News last week, golden eagles are turning up in Maine more often. They are easily confused with immature bald eagles. For decades, if someone reported a golden eagle, I was skeptical. That’s starting to change.
Bald eagles take five years to reach maturity, going through a series of plumage changes along the way. First-year birds are completely dark brown, without a hint of gold. But in the golden light of dawn, light can play tricks.
Golden eagles also change plumage as they grow to adulthood. Both bald and golden eagles develop patches of white after a year or two, but those patches appear in different places for each species.
Many people reporting golden eagles say the bird looked larger than a bald eagle, but both species are roughly the same size. It’s partly an optical illusion. Dark birds simply look larger. Golden eagles do have smaller heads. They soar with a V-shaped dihedral in their wings, whereas bald eagles hold their wings flat. But those are details only an experienced birder might notice.
The point is this: bird identification can seem difficult because birds don’t always make it easy.
Rather than fret about the similarities, rejoice in them. When you come across a twin, you don’t need to separate it from all the other birds. You only need to separate it from its doppelganger by looking for one or two diagnostic field marks.
The hardest part is remembering what they are.
