Roger Tory Peterson called them “confusing fall warblers.” He could have called them puzzling, perplexing, mystifying, bewildering, baffling or confounding fall warblers. But as the author of the first widely popular field guide to birds, he got to pick the term. Some might have considered “damnable.”
Peterson’s groundbreaking guidebook was first published in 1934 and featured two pages of warblers that don’t look like they are supposed to. On the one hand, his paintings of fall warblers recognized that our prettiest songbirds can be angelic in spring, devilish in autumn. On the other, it cemented into our heads that it is OK to be confused about them. Yes, they can be confusing, but they are not as confusing as we sometimes make them out to be.
Let’s make life easier. First, Peterson’s original guide featured 27 birds that he termed “confusing.” Fortunately, some of them are unlikely to be found in Maine. If you’re out in the woods this time of year, you can mostly eliminate those from consideration. That shrinks the confusion list down to about 20 species.
Of these, many are uncommon and won’t trouble you too often. In reality, only about 10 species can cause you headaches, and only half of those will give you frequent headaches.
Next, few birds are going to be as confusing in real life as they are painted in the Peterson book. Consider the book illustrations to be a worst-case scenario. More recent guides tend to put all of the plumage variations for a bird on the same page, rather than ostracizing the fall-plumage warblers to a different page. This is helpful because the bird you are looking at probably falls somewhere between the extremes. Having its plumage variations pictured side by side makes it easier to understand the transition to fall feathers.
Most of the confusing fall warblers in the book are male. There is less variation among females. Juvenile warblers are troublesome, but you can often assume that a streaky bird is a youngster and decide how much effort you want to put into identifying it. When you finally get down to it, the majority of the trouble is coming from only a small number of male birds. And the chief culprits usually have some kind of distinguishing feature that will help you no matter how confusing the feathered fellow is.
Yellow-rumped warblers are among the most confusing of the confusing fall warblers. Though bright in the spring, they are quite dull in the fall. It would be helpful if they were always flying away from you so that you could see the yellow rump. More often, they simply sit above your head and taunt you. Fortunately, at all ages and genders, they have streaks along the breast that are darker toward the flanks than in the center. It’s a dead giveaway that looks sort of like an inverted horseshoe.
Black-throated green warblers are abundant in Maine. In autumn, the males lose most of the black throat and the females never had much black to begin with. The rest of the bird is remarkably unchanged. It is greenish-yellow on top, yellow in the face, and has two strong wing bars. If you can get over the fact that a black-throated green warbler doesn’t have a black throat, this one gets suddenly easier to identify in the fall. Black-throated blue warblers also lose the black throat, but in all plumages it has a white spot on the wing that stands out like a pocket handkerchief.
Magnolia warblers ambush everybody. They are a common, beautiful warbler, with brilliant black streaks against a bright yellow breast. Except in fall. The streaks fade out and are barely perceptible.
Without the streaks, it looks like any other drab warbler. They also share the annoying habit of foraging in the tree above you, tormenting you with good views. Fortunately, this puts the underside of their tails on display. The magnolia warbler is unique in that the underside of the tail is white over the inner half but black over the outer. The two tone tail is visible from almost every angle — another dead giveaway in any plumage.
To be sure, there are some fall warblers that are cleverly disguised. Blackpoll and bay-breasted warblers adopt the color of an olive pit. Many chestnut-sided warblers discard all of their facial markings and any hint of chestnut. They leave for the tropics looking nothing like our birds. Oh well, I’m fashion conscious, too. I don’t wear white after Labor Day.
Bob Duchesne serves in the Maine Legislature, is president of the Penobscot Valley Chapter of Maine Audubon, created the Maine Birding Trail and is the author of the trail guidebook of the same name. He can be reached at firstname.lastname@example.org.