Picture this! Every night from now until the end of October, tens of thousands of birds are flying over our homes, winging their way south in the darkness to their wintering grounds. Sometimes that number is as high as a million! (If you want to check the action on any given night, the Cornell Lab of Ornithology’s Bird Cast website can help you with that.) Along the way, the weary migrators stop to rest and refuel.

On the morning of September 4 this year, Bear Creek Nature Park apparently looked very tempting to them! And down they glided to land in that leafy haven to find some food and just “be” until night came again, making the Wednesday morning birders very busy and very happy!

Like me, you’ve probably wondered why so many birds migrate at night. Actually there are several reasons. An Audubon article called “Listening to Migrating Birds,” explained it for me: “The stars and the moon aid night-flying birds’ navigation. Free of daytime thermals, the atmosphere is more stable, making it easier to maintain a steady course, especially for smaller birds such as warblers that might fly as slowly as 15 miles per hour. Cooler nighttime temperatures also help keep hard-working birds from overheating. And for birds that frequently wind up on the menu of hawks, cats, and other daytime predators, flying under cover of darkness can be a lifesaver.” Useful info, eh?

I wrote quite a thorough blog on migration in April last year , so I won’t review all that information here. In this blog, I just want to show you some of the forty species we saw that wonderful Wednesday morning. I’ll concentrate on the uncommon birds that we only see as they pass through during migration and some of the migrators we saw that spent the summer here raising young in our parks, but which will be departing before long.

I foolishly left my camera at home on September 4. Some days I just want to be a bird watcher! Luckily, three other birder/photographers were watching for warblers and their traveling companions at Bear Creek that day and they generously shared their photos with me. So thanks and hats off to Julie Frost, Jenne-Tai Wang (known as JT in the birding group) and Paul Birtwhistle for sharing their photos for the blog!

The Migrating Warblers

The warblers that we saw this September spent the summer mating and raising their young farther north: at the tip of Michigan’s “mitten,” in Michigan’s Upper Peninsula or as far north as the boreal forests or even the subarctic region of Canada. As you’ll see below, most spend their winters in Central or South America! Imagine those tiny wings carrying them on those long journeys twice each year!

Warblers in general are famously beautiful but notoriously difficult to identify in their fall plumage. These small birds move almost constantly among leafy branches, hungrily looking for food before setting off the next evening. Most warblers choose to stay up in the canopy, though some prefer shrubs and a few forage on the ground. Those factors also make them famously difficult for photographers. But despite all of that, here are the four warblers from the Wonderful Wednesday.

Nashville Warbler (Leiothlypis ruficapilla)

On the way into the park that morning, Paul Birtwhistle caught this lovely shot of a Nashville Warbler. What a beauty! Color patterns, wing bars and eye rings are important distinctions in identifying warblers. In Paul’s profile shot, the Nashville’s gray head, yellow throat and olive-ish breast, plus its complete, bright eye ring are the best field marks. This handsome specimen will winter in Central America, along with local birds and a lot of other warblers.

When the birding group neared the Walnut Lane in the center of the park, we could hardly keep up with each other as we shared where to look for the next bird! “At 3 o’clock in that tree behind the snag!” “At the tip of the small tree on the right!” At any given time, some folks were spotting, others were giving directions, and still others were identifying and then recording each species for our group lists on eBird.org. And of course, everyone was craning upward with their binoculars! We’ve all experienced what warbler watchers reportedly call “warbler neck!”

Blackburnian Warbler (Setophaga fusca)

Warblers’ colors during fall migration are a bit dimmed compared to their spring courting colors. But some folks spotted an orange flash in the trees and there it was, a Blackburnian Warbler! Its black and orange markings are less intense in the autumn but its distinctive triangular cheek patch is always present. Julie Frost caught it in her split-second action shot (left). You can see the same pattern in the photo shared by another photographer on iNaturalist.org who caught the bird in a less acrobatic moment.

These brightly colored birds must fit right in with birds at their wintering grounds in open forests of eastern South America where they can hang out in shade-coffee plantations.

Black-throated Green Warbler (Setophaga virens)

Nearby, someone spotted the striking Black-throated Green Warbler. Its lemon yellow head, olive green back and black throat patch are distinctive field marks. It can breed here in our area, but I personally have never seen one in the summer. Many of them keep going north to raise their young in the boreal forests of Canada. But on September 4, the one we saw was probably heading for Central America or the northern tip of South America for the winter months.

Tennessee Warbler (Leiothlypis peregrina)

During the walk down the lane, a dainty, delicately shaded Tennessee Warbler perched long enough for Julie Frost to get a great photo. She was even happier with the photo she got two days later at Bear Creek. I think both of them are wonderful!

Tennessee Warblers clearly prefer much cooler temperatures in the summer than we do! They travel to subarctic areas of Canada as well as the boreal pine forests. And now they are on their way to the warmth of Central America to spend the winter. Ornithologists sometimes refer to them as “nectar thieves,” because in tropical forests, they puncture the tube of various flowers for nectar without ever pollinating the flowers! Most birds stick their heads in flowers from the front and come out with pollen on their heads. Maybe these warblers are just a bit fastidious?

The Warbler’s Uncommon Companions in Migration

Olive-sided Flycatcher (Contopus cooperi)

Along the lane, we birders met other species that most of us had never seen before. We identified an Olive-sided Flycatcher near the lane. That one was a surprise for me and others who are familiar with summer-visiting flycatchers like the Eastern Phoebe, the Eastern Wood-Pewee, and the Eastern Kingbird. Cornell Lab of Ornithology describes this flycatcher as looking like it’s wearing an unbuttoned vest – an usefull and apt description, I think. Now it’s traveling south to bask in the warmth of South American sun, perhaps as far away as Brazil!

The Philadelphia Vireo (Vireo philadelphicus)

A Philadelphia Vireo hopped from branch to branch in the trees along the lane. Jenne-Tai Wang got a quick shot from below featuring its yellow breast, black eye line and white eyebrow. I borrowed another shot from ikso_99, an iNaturalist.org photographer, so we could see its whole appearance in a less frenetic moment.

The Philadelphia Vireo can be easily be mistaken for the Red-eyed Vireo except for its yellow breast. Its song is very similar to the Red-eyed as well; in fact it’s also been known to actually imitate the Red-eye’s song when it’s in a nearby nesting site. Ornithologists at allaboutbirds.org speculate that they do so “to avoid aggression by the larger, heavier Red-eyed Vireo.” Nature’s great at survival strategies, isn’t it?

Cornell Lab of Ornithology describes this little songster as “fairly common in dense young woodlands of Canada’s boreal summertime.” When we birders got a few, quick glimpses of this one, it was on its way south where it will travel across the continent, follow the shore around the Gulf of Mexico and settle for the winter in Central America.

Summer Residents Getting Ready to Leave

Out of the forty species we saw or heard that day – some in our birding group have great ability with song identification! – ten were migrators that we’ve seen throughout the spring and summer. They may have raised their young right here in our parks – or they may be from slightly farther north having just begun their southern migration through our area.

The Eastern Wood-Pewee is most often heard before being seen! Its questioning call gives this little flycatcher’s presence away every time. Pee-weeeeee? Listen to it at this link. Sometimes it slides up and then comically slides down into a more plaintive version of the call .

The Eastern Phoebe (Sayornis phoebe) and the Green Heron (Butorides virescens) are regular foragers at the Center Pond each summer. The Phoebe sallies forth from its branch repeatedly to snatch flying insects from the air. Watch for its tail-pumping to help identify it as a Phoebe. The heron is an excellent fisher from any overhanging branch or floating log.

Here’s a slideshow of seven other migrators we see each summer that we heard or saw on Wonderful Wednesday. These photos, though, are from other times and places; most of the forty species did not pose for our intrepid photographers that memorable morning. They were heard or seen flying overhead. These seven will be on their way south by early November at the latest.

The Grand Finale!

Just as we were leaving the trail through the Eastern Meadow to head for the parking lot, another burst of excitement! Posing calmly in a tree for several minutes was the normally elusive Yellow-billed Cuckoo (Coccyzus americanus). Yellow-billed Cuckoos breed in our parks and in many other places across the U.S. during the summer, but they are seldom seen. They tend to like dense woodlands near wetlands and stay perfectly still while hunting for their favorite food – caterpillars. No fidgeting about for the Cuckoo!

In fact, these Cuckoos are one of very few species that will eat hairy caterpillars like the Hickory Tussock Moth (Lophocampa caryae) the one that the cuckoo above caught in its beak. (Some people can suffer severe skin rashes from touching these caterpillars so if you tend to have skin sensitivity, beware!) I’ve read a Cuckoo can eat as many as 100 Tent Caterpillars or Fall Webworms at one sitting! Ornithologists report that it rolls those hairy caterpillars back forth in its bill which may be a way of trying to eliminate some of those annoying little spikes. Julie Frost got a close-up of our Cuckoo’s beak and I suspect those may be the hairs of the caterpillar clinging to its beak!

These American cuckoos are not as likely as Eurasian ones to lay their eggs in the nests of other birds, though they do occasionally add an egg in the nests of Robins, Wood Thrushes and Gray Catbirds. They tend to do so most often, though, when there’s plenty of available food in the area.

The Yellow-billed Cuckoo makes several interesting sounds. You can listen and explore the different ones at this Cornell Lab of Ornithology link.

I wanted you to see the Cuckoo’s famous long tail with its large white spots. Paul Birtwhistle took a great classic pose of this glorious bird. Can you tell that we were all pretty excited to see this usually reclusive bird at the very end of our bird walk?

The Autumn Migration Has Begun! Check It Out!

You’re welcome to join our bird walks every Wednesday morning except from Thanksgiving Week to the end of December. This season and through the winter, we start at 8:30 a.m. We have every-week members, once-in-a-while members and visitors who often become regulars. If you need a quiet walk, be aware that our bird walks are social as well as scientific. We chat as we go like friends do, but meanwhile, through eBird.org, we are citizen scientists, documenting for researchers all the species we can identify. We welcome both inexperienced birders and those who can share their birding expertise with the rest of us. You’re bound to learn something no matter what knowledge you bring to the group.

But if group birding isn’t your cup of tea, I’d still recommend hanging your binoculars around your neck and heading out into nature while the migrators are catching some R&R before nightfall. It’s an exhilarating time of year to pay attention to these intrepid creatures who briefly pass through twice each year – or those who find their way over thousands of miles to spend the summer with us. So consider taking a walk in the thin autumn sunshine and wish them, “Bon Voyage!”

[Need help with warbler identification? I use The Warbler Guide by Tom Stephenson and Scott Whittle. Cornell Lab of Ornithology’s online “Bird Academy” also offers a course on identifying warblers with lots of photos and quizzes, called Be a Better Birder: Warbler Identification.]