A yellowy bird in the maple. Not a goldfinch, not quite. Smaller, quicker, gone before you've set down the coffee. You stand at the window a while longer, in case it comes back, and it doesn't. That was the whole visit. One afternoon, one tree, one bird you couldn't put a name to.

This is the shape of fall at your window. Something drops in, stays long enough to feed or rest, and moves on before you've figured out the field marks. Most of the birds passing through right now are not the ones you know from the feeder. They are travelers. Some of them have come from the boreal forest and are trying to reach the Gulf, or further. Your maple is a rest stop.

And here is the honest part. You may not identify half of what you see this month. That's not a failing of your eye or your book. It's the season.

Spring warblers are the ones on the posters. Bright yellow, sharp black, a slash of orange at the throat. In fall, the same birds are wearing what birders call confusing plumage, and the name is not a joke. The males have moulted out of their breeding colors. Females and juveniles were subtle to begin with. What lands in your maple is often olive-yellow, faintly streaked, with a wing bar you have to squint to see. Sometimes an eye ring, sometimes not. They flit. They don't sit for portraits.

Thrushes are quieter about it. A brown bird on the ground under the shrubs, tail cocked, working through leaf litter. Could be a hermit thrush, could be a Swainson's, could be a veery on a late push south. The spotting on the breast is the tell, and the shade of the back, but you'll need a clean look and they don't often give you one. Listen for a soft chuck from the underbrush. That's them, telling each other where they are.

Sparrows come through in loose waves, mixed with the ones who live here year-round. A white-throated pops up under the feeder and you know that one, the yellow spot in front of the eye. Then a smaller one, cleaner, with a rusty crown, and you wonder. Chipping sparrow, most likely, on the way through. Then something with a streaked breast and a central spot, which is a song sparrow, or maybe a Lincoln's if you're lucky and the light is good.

So what do you do with all of this. The book, in fall, is going to have more question marks than usual. Add them anyway. A note that says small yellow warbler, faint wing bars, maple, October 8th, is a real entry. It's data. Next year you'll read it back and know more than you did.

Week by week, the cast changes. Early fall, the warblers are still moving, along with a few late flycatchers and the last of the hummingbirds if you're on their route. Mid fall, sparrow numbers pick up, white-throats and juncos start showing at the feeder for the first time since spring. Kinglets arrive in the conifers, tiny and busy, ruby-crowned and golden-crowned both. By late fall the migrants have mostly passed and your winter regulars start to settle in. Chickadees, nuthatches, downies, the jays. The feeder gets steady again.

One thing that helps. Keep the feeder full through this stretch, and keep a shallow water dish out if you can. Migrants need water more than seed, most of them, and a clean dish under the maple will bring in birds that never come to a tube feeder. That's how you get the warbler visit. Not the seed, the water.

And give yourself permission to just watch. Not every bird has to end up with a name attached. Some afternoons the whole point is the flash of yellow in the maple, the wondering, the way you stood at the window a little longer than you meant to. That counts too. Your book can hold a maybe.

If you want to sharpen the fall eye, here is the small thing. When something lands, look at the belly first, then the wing, then the face. In that order. Belly for the base color, wing for bars, face for the eye ring or the stripe through the eye. By the time you get to the face the bird is usually gone, but you'll have two of the three, and two is often enough.

Oh, look who came to the feeder. A junco, already. That's the season turning. Top up the seed before the wind picks up tonight. The travelers are still moving, and your maple is on the map.