birding – My Chicago Botanic Garden

Warblers: Rock Star Migrators

Today is National Migratory Bird Day, set smack dab in the middle of May—the month to look for warblers, vireos, thrushes, sparrows, and some shorebirds, as they migrate through the Chicago area.

Most birders might agree that the highlight this time of year is warblers. It is for me—they are tiny jewels with wings. I feel totally blessed if I can see a few during migration.

Since these birds are so small, they usually wait for favorable winds to help them travel. Any night with southerly winds will have the birds moving; new birds arrive while others depart. Every year is different, so it pays to watch the weather report if you want to see these beauties while they are passing through. The good news is that there are a few warblers that actually nest in our area, so if you miss them during migration you can often find the nesting birds later in the summer.

Palm warbler (Setophaga palmarum) — A great place to look for warblers, like this palm warbler *(Setophaga palmarum),* is in all the willow trees around the Garden.

A less common warbler is this beautiful Cape May warbler (Setophaga tigrina).

Pine warbler (Setophaga pinus) — I found this guy, you guessed it, in a pine tree. (He’s a pine warbler, *Setophaga pinus.)*

Yellow warbler (Setophaga petechia) — A yellow warbler *(Setophaga petechia)* looks for insects. These golden birds actually nest at the Garden.

Knowing when they arrive is only half the challenge. Where they will land is the second part. I’ve been surprised on many occasions to find warblers in very public places. If there is a tree, some green, or water, you have a chance at spotting a warbler. If you see a tiny bird, quickly darting in and out of a tree, there is a good chance you have found a warbler. Oaks and willow trees are particular favorites.

The birds need a food supply along the way to fuel their journey. Most of them are insect eaters, and some supplement their diet with seeds and nectar from flowers. While the cold spring delayed the plants a bit, the insects come out as soon as it is above freezing and you can see the birds darting around eating as many as they can. If you want to attract warblers to your yard, plant native trees and shrubs in your yard and be sure to add a shallow water dish.

Yellow-rumped warbler (Setophaga coronata) — Here you can see how this warbler got its name. The yellow-rumped warbler *(Setophaga coronata)* is one of the most common warblers you will see here.

Orange-crowned warbler (Vermivora celata) — A very understated orange-crowned warbler *(Vermivora celata)* keeps an eye on me.

Black-and-white warbler (Mniotilta varia) — Black-and-white warblers *(Mniotilta varia)* can be found hopping up and down the bark of trees looking for insects.

Migrating birds are one of nature’s greatest wonders. Different birds migrate at different times of the year, but all told, millions of birds make the trip north and south each year, navigating all sorts of hazards along the way. I am in awe of these tiny birds that travel so many miles. They are the elite athletes of the avian world.

The cooler than average spring did allow a few loons to stay longer than usual around the Garden. It was really fun seeing them stealthily appear from seemingly out of nowhere. A major rarity showed up for just one day, a white-faced ibis. I was lucky to be around to see it; a first for me, and I believe the Garden as well.

White-faced ibis (Plegadis chihi) — Wow, what a treat! I’ve never seen this bird before. White-faced ibis *(Plegadis chihi)* is a very rare visitor to the area.

The first wave of warblers arrived early in May and many from that group have moved on, although you can still see palm, yellow-rumped, black-and-white, and Nashville warblers at the Garden now. There should be several more waves before the month is over, as well as a few interesting sparrows and vireos. Warblers migrate at slightly different times. There are those that show up at the end of April and early May, those that you will see mid-month, and a few late ones that show up at the very end of the month. I like to go out every day in May, just in case a new wave of warblers has shown up, I hope you will too!

Warbling vireo (Vireo gilvus) — The warbling vireo *(Vireo gilvus)*—not a warbler, but its song sounds like one.

Join me and #birdthepreserves this month. My top five migration places to visit in the spring are the Chicago Botanic Garden, Montrose Point Bird Sanctuary (the magic hedge) in Chicago, The Grove in Glenview, LaBagh Woods in Chicago, and Ryerson Woods in Deerfield.

Spring is for the Birds at the Garden

“Baltimore oriole,” my husband Chuck called out—and there it was, its orange coloring glowing so brightly in the morning sun that it seemed lit from within. The bird almost seemed to be posing for us, perching in full view on a nearby tree branch and bobbing its black head as it sang.

Al Stokie, our expert birding companion, recorded it in his notebook; it would become part of the weekly bird survey he supplies to the Chicago Botanic Garden.

We continued on our walk through a wonder of the natural world that anyone in the Chicago area can see for the price of a pair of binoculars: spring bird migration.

Every spring, small, colorful warblers fly through the Chicago area on their way from their winter homes in Central and South America to their nesting grounds in the northern United States, Canada, and as far north as the Arctic Circle. And every year, birders at the Garden and beyond delight in the sight.

“In May, you always go crazy,” said Stokie, who has become the official compiler of the Garden’s bird statistics.

Blackburnian warbler. — Blackburnian warbler

But May isn’t just for experienced birders; the birds are so numerous and their breeding plumage so gorgeous that it’s a perfect time for anyone to explore bird-watching. The 385 acres of the Garden are an excellent place to start. “The Garden is a pretty well-known spot for birding,” said Jim Steffen, the senior ecologist who oversees the Garden’s bird-friendly practices and its cumulative bird list, which currently numbers 255 species.

Come #birdthepreserves with the Forest Preserves of Cook County. View the list of upcoming events for free events near you.

Learn about the bird of the month at birding events at your local forest preserves.

And the Garden has worked with the Forest Preserves of Cook County’s #birdthepreserves initiative. There are events at the preserves, and a different bird is featured each month.

Where to look for birds at the Garden? It depends.

“You bird the Garden at different times of the year in different places,” Stokie said. “May is warbler month, and warblers are found in the woods.” So he started us off in the McDonald Woods, in the Garden’s northeast corner. We walked along the wood-chipped path, and on boardwalks and bridges over streams and ephemeral ponds, watching for movement in the trees. It was a blustery morning. “Our problem today is going to be the wind,” Stokie said, and he was right. We saw blue-gray gnatcatchers, catbirds, ovenbirds, and that beautiful oriole. And when we got to a small forest pond, we saw a solitary sandpiper scurrying through the water on its stick-like legs.

Stokie saw far more than I did—he recorded 48 species—but we didn’t get the full-on spring migration blast of birds.

You might, though.

The peak of spring migration is typically May 10 – 20, and International Migratory Bird Day is on the second Saturday in May. Most of the warblers will still be moving through in the next few weeks, Steffen said, and there should be flycatchers, goldfinches, woodpeckers, and orioles. Around the Garden Lakes, he said, people can see wood ducks, mallards, night herons, green herons, and great blue herons.

Ruby-crowned kinglet. — Ruby-crowned kinglet

It’s a grand sight. But along with the beauty, Steffen sees cause for concern due to climate change. Trees are leafing out earlier, before the warblers—cued by the lengthening of days—arrive. “The buds are already open, and the insects associated with them are gone,” Steffen said. “It’s messing up the synchronization.”

The best places to see birds at the Garden in spring, Stokie says, depend on the bird. Warblers and vireos will be in woodlands like the McDonald Woods and the Barbara Brown Nature Reserve at the Garden’s southeast corner. Sparrows will be in open areas like the Dixon Prairie; and shorebirds and late migrating ducks will be found in the wet areas just north of Dundee Road.

Hairy woodpecker

Sign up for a bird walk with an expert. Check the calendar for bird and nature walks.

Or go to any forest preserve or park. Look for people with binoculars, and ask what they’re seeing. You’ll be off and birding.

For Some Birds, Constructing a Nest Could Be a Stretch

While working out in the woods this winter, a small lump on the branch of a young elm tree caught my attention. At first I thought it might be a gall, or an injury that had healed-over. On closer inspection, the lump turned out to be a ruby-throated hummingbird nest from last summer.

Although I see hummingbirds regularly at the Chicago Botanic Garden, I rarely encounter one of their nests. Hummingbirds themselves are amazing, but their nests are truly a marvel of avian architecture. Not much larger in diameter than a quarter, they are just large enough to hold the one to three navy bean-sized eggs of the hummer. For the pint-sized bird to be able to keep the tiny eggs warm during incubation requires that the nest be not much larger than her body.

PHOTO: Hummingbird nest and quarter (for scale). — Not much larger than a quarter, the ruby-throated hummingbird nest is an engineering marvel.

This is all well and good until the eggs hatch. Growing young hummingbirds can double or triple the amount of room necessary to hold the family. One of the ways the hummingbirds get around this need for flexibility is that they construct the nest of soft plant fibers and then wrap the whole thing with spiderweb silk. This creates an elastic nest that has the ability to expand as the contents of the nest increases. Can you imagine yourself going out and plucking a strand of sticky silk from a spider web with your fingers and then trying to use it to build something out of lightweight fuzzy plant fibers? I imagine you might find yourself wrapped up in a ball like some sort of oversized grotesque moth cocoon. The silk also helps to anchor the nest to the top surface of a horizontal branch.

PHOTO: Spiderweb silk is used by hummingbirds as a nest liner. — Spiderweb silk: the expandable nest liner preferred by hummingbirds.

Keeping the nest just the right size as the need arises helps to keep the growing youngsters warm and secure. In the western states where several species of hummingbirds nest, often at higher elevations, it is not only important to keep the nestlings warm, but also the incubating female, especially at night. Therefore, it is often the case that hummingbirds in these colder situations will locate their nests on a limb with an overhanging branch acting as a sort of roof to help block the nest from the night sky.

Although this measure helps reduce heat loss, it is often the case that nesting females will go into a state of torpor (reduced physiological activity to lower body temperature) in order to conserve energy on particularly cold nights. This is a principle of physics in which the larger the difference in temperature between objects, the faster the heat flows from the warmer one to the cooler one. Therefore, a hummingbird with a lower body temperature will lose heat more slowly than the one with a warmer body. As I stated earlier, hummingbirds are amazing!

PHOTO: Parmelia sulcata, a common lichen, is used to help disguise the hummingbird's nest. — *Parmelia sulcata*, a common lichen, is used to help disguise the hummingbird’s nest.

Part of the reason—besides size—I had not noticed the nest earlier is that the birds do a fantastic job of camouflaging it. This also relates to the spiderweb silk. Some or all of the silk used is sticky. Upon completion of nest construction, the birds collect bits of lichen and attach them to the sticky strands on the outside of the nest. Interestingly, the birds seem to always use the same species of lichen, one that goes by the name of Parmelia sulcata.

Parmelia sulcata is a light greenish-gray lichen with a leafy (foliose) appearance. One of our more common lichens, it is often seen on the upper branches of trees, and was particularly abundant on the ash trees that died from emerald ash borer. I don’t know if the birds chose this species of lichen in particular or, being common, it is just found most often. It is also interesting that the birds seem to apply the lichens to the nest in an upright position, with the top facing outward, so they look like they could be growing on the nest.

Come birding at the Garden! Take a birding class; join a group, and check your finds against our bird list.

Although this process is fascinating, it is not restricted to hummingbirds. One of the other breeding birds at the Garden utilizes a very similar nest construction technique to hold its three to five small eggs. The blue-gray gnatcatcher, another tiny bird (that somewhat resembles a miniature catbird in appearance and sound), also constructs a nest out of soft plant fibers, including spiderwebs, and applies lichen to the outside of its nest. A nest of this species, a little larger than that of a hummingbird, was found on a branch of one of the locust trees growing in a Garden parking lot.

PHOTO: A female ruby-throated hummingbird (males have the ruby coloring) enjoys a sip of salvia nectar in Circle Garden in summer. — A female ruby-throated hummingbird (males have the ruby coloring) enjoys a sip of salvia nectar in Circle Garden in summer.

PHOTO: A blue-gray gnatcatcher at the Garden; females look similar, but are less blue. — A blue-gray gnatcatcher at the Garden; females look similar, but are less blue.

If you’re lucky, you might find the nest of one of these birds during the nesting season, but if not, keep an eye out for little bumps, lumps, and knobs on bare branches in winter. You might get lucky.

Come #birdthepreserves with the Forest Preserves of Cook County. View our list of upcoming events for free events near you.

Osprey Nesting Platform Installed at the Garden

Look up! In partnership with Friends of the Chicago River (FOCR) and the Forest Preserves of Cook County (FPCC), an osprey nesting platform was installed on Friday, January 29, along the North Branch Trail at the south end of the Chicago Botanic Garden near Dundee Road.

MAP — The Garden’s new osprey nesting platform is located near Dundee Road and is viewable from the North Branch Trail.

The osprey is listed as an endangered species in Illinois, which means it’s at risk of disappearing as a breeding species. Fish-eating raptors that migrate south and winter from the southern United States to South America, osprey are often seen during their migrations—yet few remain in Illinois to nest. The lack of suitable nesting structures has been identified as a limiting factor to their breeding success here.

Males attract their mates to their strategically chosen nesting location in the spring. In order for a nest to be successful, it must be located near water (their diet consists exclusively of fish, with largemouth bass and perch among their favorites), the nest must be higher than any other nearby structure, and it must be resistant to predators (think raccoons) climbing the nest pole and attacking the young.

FOCR and the FPCC sought out the Garden as a partner for an installation site, in large part owing to the Garden’s strong conservation messaging and proximity to other nearby nesting platforms that have been recently installed (two are located alongside the FPCC’s Skokie Lagoons just to the south).

The Garden’s nesting platform was installed atop an 80-foot “telephone pole,” set 10 feet into the ground and extending upwards by 70 feet. The 40-inch hexagonal nest platform atop the pole has a wire mesh on the bottom so that water can pass through the sticks and stems that the osprey will bring to construct the nest.

PHOTO: Installing and osprey nesting pole. — A truck-mounted auger and crane set the nesting pole and platform into place.

PHOTO: Installing an osprey nesting pole. — The nesting platform sits atop the pole and is ideally sized for a future osprey nest; notice that we even “staged” the new osprey home with a few sticks of our own!

With the osprey nesting platform now in place, our hope is that within the next few years, a migrating male will select the site and pair with a female. Osprey generally mate for life, though they’re together only during the breeding and rearing seasons.

You can learn more about the how and why of the osprey nesting platform project at the FOCR website. Follow the links on that webpage for images, video, and a press release relating to the installation of an identical osprey platform at the Skokie Lagoons last spring.

Read more about the long-term effort, and about ospreys making a comeback in Cook County. Discover birding at the Garden and find our full bird list online at chicagobotanic.org/birds.

Warbler Heaven

A lot of birds migrate through the area this time of year, but I have to say warblers are my favorites. The other day, when the rain cleared and the sun came out, I found myself in warbler heaven!

PHOTO: Yellow-rumped warbler. — Yellow-rumped warblers (*Setophaga coronata*) are some of the most common warblers to be seen at the Garden. You can spot them almost anywhere! Photo © Carol Freeman

As soon as I walked out of the Visitor Center, I saw movement in the trees next to the bridge: my first warbler of the day—a prothonotary! (Protonotaria citrea)—an uncommon warbler, and the first time I’ve ever seen one at the Chicago Botanic Garden! Next stop: the top of the Waterfall Garden. The birds were hopping! Here I added eight more warbler species, including yellow-rumped, palm, black-and-white, Cape May, American redstart, Wilson’s, magnolia, and yellow warblers! Wow! So much fun! I also saw red-eyed and warbling vireos, a scarlet tanager, and a ruby-crowned kinglet, to name a few.

PHOTO: Red-eyed vireo. — Another lovely migrant: the red-eyed vireo ( *Vireo olivaceus*) Photo © Carol Freeman

PHOTO: Black-and-white warbler. — The black-and-white warblers (*Mniotilta varia*) can be seen hopping along branches looking for insects. Photo © Carol Freeman

After delighting in the abundance of birds for a few hours, I slowly made my way back to my car, choosing to walk under the amazing flowering crabapple trees. Just at the end of the line of trees I heard what I thought was another warbler. I couldn’t quite see what it was. I tried calling it out, and to my delight, out popped the most beautiful male northern parula warbler (Setophaga americana). He hopped right onto a flower-filled branch and seemed to pose while I got some photos. I’ve only seen a parula a couple of times before, and never this close, and never on such a pretty perch. A perfect way to end my journey in warbler heaven.

PHOTO: Northern parula warbler. — I could hardly believe my eyes when this beauty popped up in the flowering crabapple tree! Northern parula warbler (*Setophaga americana*) photo © Carol Freeman

While I can’t promise you will see this many warblers in a day, there is always something to see, and the fun part for me is never knowing just what might show up. Last week it was a white-eyed vireo (Vireo griseus). This week, warblers. Next week, who knows? All I do know is I’ll be out there to see what wonders there are to discover and then I’ll be in heaven again.