Welcome back to the Entryway to Birding blog! We’re moving into September and fall migration continues to pick up. Unlike spring migration, which sometimes feels like it’s gone in a flash, fall migration is more of a slow burn—which is good news for us birders! It means we have more time to enjoy and seek out the wide variety of migrating birds that are passing through on their long, arduous journey south for the winter.
What does September bring us during fall migration? Shorebirds are still around, though not in as great of numbers as earlier in the season. This week’s rain will hopefully revive some popular mudflats that shorebirds have been using as stopovers. Common nighthawk migration continues, with these erratic flyers picking bugs from the sky at dusk and dawn. But this past week has seen a surge in passerine migration—songbirds like thrushes, vireos, flycatchers, and, oh yes, warblers are all here and fueling up for their migration south.
Warblers. A fan favorite. They’re fast. They’re small. They’re often infuriatingly high up in the trees and obscured by leaves. But oh, we love them so.
If you’re a new birder, you’ve maybe heard tell that fall warblers are “confusing.” Why is that? How are they different from spring warblers? What is it that you’re up against? This week’s Entryway to Birding blog brings you a guide to finding and identifying fall warblers with confidence.
A Tennessee warbler perches on branch after eating a bug. This species is one of the more prolific warblers we’re seeing right now, and it’s a bit unusual in that it bucks the fall trend—unlike other warblers who don some drab and muted colors, the Tennessee’s plumage is actually brighter in the fall than in the spring. Photo by Caitlyn Schuchhardt
Spring vs Fall
A chestnut-sided warbler in bright spring plumage sings on a branch. Come fall, these birds are hush hush. Photo by Brandyn Kerscher
During spring migration, birds are traveling south to north—leaving their southern destinations where they’ve spent the winter and heading north to their breeding grounds, where they will mate and reproduce. When we see warblers come through in the spring, they’re looking fancy, adorned with bright colors and singing away. They’re out to attract a mate and you’re more likely to see them perch on a branch while they belt out a song. IDing these spring warblers feels a little more instinctive when you can see the bright crisp plumage and match it with a song.
During fall migration, birds are traveling north to south—leaving their breeding grounds and heading to their wintering destinations where they’ll be able to find food that they wouldn’t be able to find if they stayed further north in the colder months. The breeding season is over and their bright, flashy plumage isn’t as bright and flashy—and they’re no longer belting out any tunes. Now they are laying low, their attention hyper-focused on eating bugs and fueling up for the long journey ahead.
While most will look similar to what you’d see in spring, albeit a little faded, a select few will throw you for a loop and change up their entire plumage. You’ll also see a lot more birds in immature plumage since there is a whole new generation of young birds making their first migration. This is why IDing fall warblers has become known as a challenge—there’s just a few extra hurdles you have to consider before making your ID.
Take a look at these Blackburnian warbler photos I took—one this past spring and one this fall. The bright vivid orange face is now a lighter yellow, the once bold streaking is now faint, but the overall pattern matches up. Many of the warblers you see will have this “faded” style of plumage (though their colors don’t actually fade—this is a new set of feathers.)
Here’s a common yellowthroat. It’s lacking the male’s signature black mask, so this is either a female or an immature male. You’ll see a lot of this species right now—in the absence of the mask, look for their namesake, that bright yellow throat. Photo by Caitlyn Schuchhardt
As an aside, spring arguably poses some of the exact same challenges as fall. You might not see birds in immature plumage but you will see female adult birds. And guess what? The plumage of an immature male bird often looks like … you guessed it, a female adult. The difference is that fall just brings a lot more immature birds so it will feel like you encounter trickier plumages more often. It’s really a good argument for everyone to spend more time studying up on female plumage!
Do not let these “challenges” deter you. Yes, warblers can feel intimidating—especially when you’re a new birder. Yes, you might go out in search of them and not be able to ID a single one. That is okay. Do not be discouraged. It takes practice. It takes time to get familiar with them and all the weird angles you’ll view them from. I struggle to ID most warblers while I’m out in the field (even in spring when they are theoretically “easier”) and I rely heavily on my camera to snap photos that I can use to study and compare to my field guide.
So if you’re up for it—and I hope you are—let’s talk about where you can find these fall beauties, who are gorgeous even in their “drab” plumage.
The When and Where of Warblers
Did you know that during migration, many birds—warblers included—will migrate at night? Under the cover of darkness, they face less risks of getting caught by predators. But after a long night of flying, they’re hungry and need to refuel on a breakfast of bugs. Your best opportunity to see them in good numbers is early morning, after sunrise, when the sun has begun to warm the trees and all the bugs hiding there.
Choosing your destination takes a little planning. Despite ample sun, you won’t have luck in an open prairie. Despite ample trees, you won’t have luck in the thick of the woods at dawn, where it may be too chilly for bugs to be moving yet. Think about choosing a location that has good “edges” where you have thick vegetation bordering a clearing or path, where the bushes and trees can be warmed by the sun in the morning.
I took this photo at Ho Nee Um, part of the UW-Madison Arboretum. This is a great hotspot for warblers, as it has a lot of mixed habitat with good edges that get morning light. Photo by Caitlyn Schuchhardt
These “edges” may be in a county park parking lot (parking lots are oddly great for warbs!), or near a picnic area at a state park, or along a path that skirts between a prairie and some woods. Think about some of your favorite birding destinations and some good mixed habitat areas that face east to get the morning light. Bonus points if you can find a spot that’s sheltered from the wind. Wind can be your enemy and keep birds deep in the vegetation—it also shakes a lot of leaves and makes it really hard to focus on movement in the trees when everything is moving.
Here’s an aerial view of the entry road at Cherokee South. Park at the first lot and walk the gravel road—shoot for early morning when the sun is warming up the trees on the west side of the road. I’ve had great luck with warbler flocks here! The highlighted orange areas are where I tend to find warblers in the morning. Screenshot from Google Maps
Having some analysis paralysis and can’t decide where to go?
If you’re in the Madison area and want to get some really good warbler practice, park in the first lot of the South Unit of Cherokee Marsh, just off the corner of Wheeler Rd and School Rd and walk the gravel road near the entrance. The trees on the west side get great morning light and I’ve found that I get closer looks at warblers here, since the trees are so close to the path and many of the warblers I’ve seen have been mid- or low-level.
Other popular warbler destinations include Cherokee North, the Lakeshore Nature Preserve, Lake Kegonsa State Park, and the UW-Arboretum. This should be a good list to get you started!
Pro tip: Google Maps can be your friend. Look at a satellite view of some of your favorite parks and see if you can identify some good “edges” that face east to get morning light.
The Hard Part — Making an ID
You’ve found a spot. The sun is warming things up. Slowly, the birds begin to emerge and snatch up those early morning bugs. You lock your eyes on one and raise your binoculars to see a … huh. Hmm. Uhhhh. Hmmmmmm. Oh! Wait. No. … Ahhh! Come back!
Anti-climactic, isn’t it? But that’s the soundtrack to my average warbler session, spring or fall. These birds are hard. Warblers reward patience, so don’t give up or feel discouraged. I’ve got a few tips to help you out as you pick your way through a warbler flock:
1. Make sure you’re looking at a warbler
Not a warbler! I repeat, not a warbler! Though I 100% thought it was at first. This is a yellow-throated vireo. Notice the bigger, rounder head and the thin tail. You can’t see the teeny hook on the bill in this photo but you can get a sense of how the bill looks “heavier.” Photo by Caitlyn Schuchhardt
Yeah, this sounds obvious, but it’s very easy to get fooled by a vireo. Right now, we’re seeing a lot of red-eyed vireos, yellow-throated vireos, and Philadelphia vireos. These birds are a little larger than warblers, but size can be incredibly hard to determine in the field. They’ll often feed with warblers in a mixed flock and blend right in. Careful observations of their bill and head can set you straight, though. They’ll have a rounder, more distinct head and their bill will be thicker than a warbler’s. And if you get a good look at the bill, you’ll notice that a vireo’s bill will have a a very small, hooked tip—no warbler has that!
2. Know where on the bird to look
To make an ID, you’ll want to take note of some key features of a warbler’s plumage. Are there markings on the face, like an eyeline, an eyebrow, a cheek patch, or a dark throat? Are there wing bars? What color(s) is the undertail and undertail coverts?
Notice the black tail tip, white tail base, and white undertail coverts. Even if that’s all you saw, you could ID this bird with practice. This is a magnolia warbler, which usually has dark streaking down the sides of it’s yellow chest. You can barely see the streaking in this image, it’s so faint. That’s why the tail and undertail coverts can help you out! Photo by Caitlyn Schuchhardt
The what now? Yep, this confused me at first too. But if you want to get good at warbler ID, you need to know where to find these. The undertail is obvious—it’s the underside of the tail and it often has unique coloring or marking that can lead to an ID. The undertail coverts are the set of feathers that transition between the bird’s belly and the tail. The coloring of the undertail coverts can often help narrow an ID as well.
You’ll spend a LOT of time looking at warblers from below, since many like to forage high up in trees. Knowing a few common undertail and undertail covert patterns can help you get faster at IDs in the field. Check out this article from The Birdist for more tips on IDing warblers from below.
3. Expect dull and drab—but still familiar—plumages
Here’s a blue-winged warbler, looking … pretty much like he did in spring, maybe just not as vibrant. Not all fall warblers are confusing! Photo by Caitlyn Schuchhardt
By and large, most of the warblers you encounter (with three notable exceptions) will be sporting a faded version of their spring plumage. A blue-winged warbler will still look like a blue-winged warbler with it’s all yellow chest, white wingbars, and dark eyeline. A magnolia warbler, which usually has dark streaking on its sides in spring, may only have very faint streaking in fall, much like how the dark necklace of a Canada warbler will look lighter and faded too. A palm warbler may lack its trusty brown cap, but you might be surprised at how familiar it feels when you see one. (It helps that this species is often found on the ground or in low brush, still pumping its tail like it does in spring.)
There are three warblers you can expect to really fool you by donning a whole new outfit, and those would be: chestnut-sided warbler, blackpoll warbler, and bay-breasted warbler. Of the three, chestnut-sided becomes pretty easy to identify in fall once you know what you’re looking for—it’s got a strong white eyering, a lime-green back with a gray chest, and two yellow wingbars.
Chestnut-sided warblers, like the one pictured here, really do switch up their outfits. Once you learn their new look, they’ll be pretty easy to spot. I mean, look at that lime-green back! That plus the eyering and yellow wingbars seals the deal. You can even see a liiiiiittle bit of the “chestnut” on the flanks, but only barely—this can vary a lot bird by bird. Photo by Brandyn Kerscher
As for blackpoll and bay-breasted? These species unfortunately look very similar in their fall plumages, and feel beyond my skill level at this point. If you’re up for a challenge and want to ID these species, check out this helpful comparison, written by some much more experienced Wisconsin birders.
A Few Notes and Bits of Advice
If you’re on eBird and nervous about not being able to ID birds on your list, don’t fret. Enter your count (or your best guess at a count) under “warbler sp.” and it will still help to document that warblers were present during your birding session!
If you can get a photo, try running it through Merlin’s photo ID. I’ll take a bunch of photos in the field to capture some different angles—like face, wing bars, and undertail coverts—and then use a field guide to try and identify the bird at home. Once I have a solid guess, I’ll run a picture through Merlin and see if I’m close. If both IDs align, then I know I’m in good territory.
If you’re struggling to even see warblers, step back and look at the scene around you. Don’t focus on any particular tree, just absorb the scene. Then try and notice movement—especially things like a bouncing branch, which might have been a warbler hopping onto a branch or hopping off. You’ll start to distinguish regular wind/leaf movement from bird movement.
Once you’ve identified movement and a potential bird, keep your eyes locked on it. Slowly raise your binoculars to your face. If you lose sight of the bird, don’t try and search for it through your bins. Lower them a bit, find it with your eyes again, then raise your binoculars to get a closer look. And don’t look down at your binoculars as you bring them to your face, either—it’s easy to do this, but you really want to keep your eyes locked on that bird or movement.
Wanna deep dive? Get The Warbler Guide!
Look at all those helpful photos! If you keep flipping, you’ll get a ton of info on songs, calls, behavior and more, but right now, these pictures have been helping me most. Photo by Caitlyn Schuchhardt
If you’re committed to improving your warbler identification skills, then you should look into getting a copy of The Warbler Guide by Tom Stephenson and Scott Whittle. I ordered a copy earlier this summer and have found it to be really helpful. It is jam-packed with features and information—more than I need at my stage of birding, but stuff I’m sure I’ll get to later.
What I love are the ID pages—they are laid out wonderfully and have multiple pictures of each species in its varying plumages, including from weird angles that you might actually expect to see in the field. As much as I love my trusty Sibley’s, it doesn’t help me much with warblers because I rarely see a bird posing so nicely to compare it to the guide. The Warbler Guide gives me all the angles that help me get a sense for what the bird will look like when I encounter it as it searches for bugs in the treetops.
A selection from The Warbler Guide’s quick guides, which you can download for free here.
The Warbler Guide has a website with online resources too—including some free quick guide handouts to help you ID warblers in the field.
Remember those undertails and undertail coverts we talked about? They’ve got a quick guide for that! The quick guides are PDFs that you can download to your phone or print to stick in your pocket while you’re out in the field. (You don’t want to carry The Warbler Guide itself out into the field. It’s built like a brick.)
If you’ve taken anything away from this post, hopefully it’s that you shouldn’t feel discouraged if you’re struggling to ID warblers. They are tough in any season, but the more you get out there and try, the better you’ll be.
And if you can’t ID them, so what? Worst case scenario is that you’ll have had a lovely morning looking at some pretty freakin’ cool birds. They’ve traveled hundreds and hundreds of miles, with hundreds more to go. You get to enjoy them during their journey, so soak it up. You can enjoy a rotating selection of these beauties throughout September and into October, but once they leave this fall, they won’t be back til May!
Happy birding, everyone! I’ll see you next week!
____
Caitlyn is the Communications and Outreach Assistant at Madison Audubon. She’s crazy for birds because they changed her life. She’ll be back next Monday with some tips and tools for birders, new and experienced! Between now and then, she’d love to hear about the birds you’re seeing and hearing. Leave a comment below or email to drop her a line!
