May 22, 2019
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People don’t become good at bird identification by being right all the time

Courtesy of Bob Duchesne
Courtesy of Bob Duchesne
Rusty blackbird populations have decreased by 90 percent since the 1950s. The birds are common in Maine during the summer, when it's difficult to assess the population on their wet, dense and buggy breeding grounds. Luckily, the birds flock together after leaving Maine and can be easily counted in the southern U.S. during the Christmas Bird Count.

People send me photos, hoping I can identify a strange bird they’ve just seen. I enjoy doing it. But I also secretly cringe. A bird in the wild gives all sorts of clues to its identity. You can see the field marks as it moves around. You can note how it acts, where it sits, what it’s feeding on, how it behaves around other birds and even what it sounds like. But in the typical photo, all you can see is one angle, usually distant and blurry, and there’s no way to distinguish relative size.

A few weeks ago, a reader in Hermon sent me a photo of an unusual bird that was visiting her feeder on the back deck. She wondered if it might be a varied thrush, even though that’s a western bird. In truth, the varied thrush does wander east, and at least one has been seen in southern Maine this winter. I looked at the blurry photo, and could make out a bronze colored bird, roughly the size of a robin, with a long pointed bill, and the distinct impression of a dusky mask around the eye. Furthermore, visiting a backyard feeder is exactly what a lost varied thrush would do. She was right!

[Read more Good Birding here]

Except that I was wrong. With more views of better photos, the bird turned out to be a female rusty blackbird.

Secretly, I rejoiced at being wrong. People don’t become good at bird identification by being right all the time. They get better by being wrong, and then remembering the mistake. There’s nothing like a good mistake to sear a particular field mark into your brain. For example, a rusty blackbird has a white eye. The varied thrush eye is black. That wasn’t visible in the original photo, but it was obvious in later ones.

Golden eagles are my nemesis. People often report golden eagles, even though they’re actually seeing an immature bald eagle. When I receive such a photo, I immediately start running down the checklist in my mind. People who report golden eagles frequently exclaim that the bird is huge, larger than a bald eagle. In real life, the two eagles are the same size. As with most raptors, females of both species are larger than males, and immatures are larger than their parents, because their parents have just spent the past few months stuffing them with free food. Thus, a “huge” eagle is more likely to be a young bald eagle.

[Video: ‘The Great Chickadee Debate of 2019’ ends without choosing one state bird]

Bald eagles have bigger heads and bills. Golden eagles have feathers covering the entire leg, whereas the lower leg of a bald eagle is bare. At certain plumages, both eagles have white patches underneath, but the patches are in entirely different places. Bald eagles soar with their wings straight out, flat as a board. Golden eagles soar with their wings tilted upward in a slight v-shaped dihedral.

Of course, none of these field marks are visible in the blurry photos I’m sent. All I can see is a big, dark bird of uncertain size, with legs and plumage patterns hidden from the camera. Be aware that I am absolutely capable of making an identification mistake.

[Just when you think you have hawks figured out, a new one shows up]

Meanwhile, having a rusty blackbird at one’s feeder is good news. She continues to make daily visits, and I hope she survives the winter. While a wandering varied thrush from out west is a cool bird to have in the backyard, the rusty blackbird is much more in need of saving. The rusty blackbird breeds in Maine, but it’s hard to say how much longer that will be true. It’s disappearing from the planet faster than almost all other birds.

The collapse of the rusty blackbird population is epic, but it took awhile to notice. It’s a hard bird to study because it nests in boggy portions of northern spruce forests. It winters in equally damp southern swamps. They’re difficult to access.

[Video: Go winter birding at Reid State Park]

It’s becoming clear that many things are contributing to the population collapse. Due to climate change and deforestation, 30 percent of the continent’s northern wetlands have simply dried up. Mercury from coal-fired power plants and other sources has contaminated their feeding grounds. On their winter territories, they are sometimes the victim of blackbird eradication programs, targeted at abundant red-winged blackbird and grackle flocks around southern grain fields.

So we’re all rooting for this young lady, and we hope she flies north soon to lay some eggs.

Meanwhile, keep those photos coming. My mistakes are making me a better birder.

Bob Duchesne serves as vice president of Maine Audubon’s Penobscot Valley Chapter. He developed the Maine Birding Trail, with information at mainebirdingtrail.com. He can be reached at duchesne@midmaine.com.



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