Birding – Page 3 – My Chicago Botanic Garden

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.

Winter Birds Are Here!

The flowers are gone, the trees are bare, now what to photograph? Birds, of course! Winter is a great time to get some fabulous shots of winter birds. One huge bonus is that there are no leaves on the trees and the birds are much easier to see!

There are the “regular” local birds, like robins (yes, some robins do stay around all winter), goldfinches, cardinals, chickadees, mallards, Canada geese, red-tailed hawks, and cedar waxwings, to name a few. Plus, winter has the bonus of birds that actually migrate to our area just for the winter. Some migrants you will see every year are juncos, tree sparrows, and a variety of ducks. Other birds are occasional, or eruptive, and only show up once every few years, like pine siskins, red-breasted nuthatches, and redpolls. Then there are the, “wow! I’m really lucky to find this species!” birds, like crossbills, snowy owls, bald eagles, and bohemian waxwings. That is the fun part—you never know what you will find on any given day. That is why I go out every chance I get!

You can check the list of birds that you can expect to see at the Garden here.

Goldfinch in toned-down winter plumage, enjoying seeds on Dixon Prairie. — A goldfinch in toned-down winter plumage enjoys seeds on the Dixon Prairie. ©Carol Freeman

Male cardinal surveying the bounty on the prairie. — A male cardinal surveys the bounty on the prairie. ©Carol Freeman

Common redpoll feasting on birch tree seeds around the Regenstein building. It was a nice find to see this occasional visitor at the garden. — This common redpoll was feasting on birch tree seeds around the Regenstein Center. It was a nice find to see this occasional visitor at the Garden. ©Carol Freeman

When you get to the Garden, some places to look are all the trees with berries! Yes, the birds love them. Another good place to look is the Dixon Prairie, where all those seeds attract a lot of birds. Be sure to check out the bird feeders at the Buehler Enabling Garden too. You can also find a variety of birds—especially woodpeckers—in the McDonald Woods. If there is open water, check there for ducks and geese. You might be surprised at just how many birds you can find in winter.

What a surprise to find this adult bald eagle sitting in a tree just next to the Plant Science building! — What a surprise to find this adult bald eagle sitting in a tree just next to the Daniel F. and Ada L. Rice Plant Conservation Science Center! ©Carol Freeman

The local Robins are taking advantage of the abundant food supply at the garden. — The local robins take advantage of the abundant food supply at the Garden. ©Carol Freeman

The pine siskins were enjoying the bounty at the Enabling Garden bird feeders. — The pine siskins enjoy the thistle seeds at the Enabling Garden bird feeders. ©Carol Freeman

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.

PHOTO: Palm warbler. — Palm warblers (*Setophaga palmarum*) can easily be identified by their tail pumping and rusty crown. Photo © Carol Freeman

PHOTO: White-eyed vireo. — An uncommon visitor! I was surprised to find this white-eyed vireo (*Vireo griseus*) in a tree in a parking lot. Photo © Carol Freeman

Adriana’s Bird of the Day is the Kingfisher

A partial transcript of my first official bird walk:

Me: What was that call?

Expert birder: A chipmunk.

Me: What’s that big brown thing in the branches? It’s shaped kinda like a hawk.

Expert: Dead leaves. We call that a fake-out.

Me: Right.

Expert: Do you hear that rattle? I hear a kingfisher!

I really do not hear the rattle, but I feel a rush of excitement as I chase my guide along the trail of the Barbara Brown Nature Reserve at the southeast corner of the Chicago Botanic Garden. The tree-lined pond is one of many different habitats that make the Garden an excellent place for birders experienced and otherwise. Adding to my great fortune are golden sunshine—lighting the first red, orange, and yellow leaves of autumn—and the presence of Al Stokie, who comes to the Garden every week to report on shorebirds and other avian visitors. I’m tagging along on one of his early morning surveys and gleaning basic principles of birding.

Several area bird clubs—including the Lake County Audubon Society (an Illinois Chapter of the National Audubon Society) and the Evanston North Shore Bird Club—welcome beginning birders to their regular meetings and field trips.

Al Stokie comes to the Garden weekly to monitor bird populations. He files his counts on the IBET website.

It’s seasonal

Our first stop was the expansive deck of the Kleinman Family Cove, one of Al’s favorite spots for viewing the North Lake. In just a few weeks the surface would be filling with ducks stopping to rest on their way south for the winter. They’ll be followed in November by grebes and red-breasted mergansers. Native plants surrounding the cove attract a variety of birds, but most of the tiny warblers left for warmer climes weeks ago. McDonald Woods, a restored native oak woodland, is the place to go in the spring to catch the warblers’ return and, if you’ve got really good eyes, a place to spot owls in the winter.

“It’s all seasonal,” says Stokie. “Every month of the year you can go out and see different things.” I like that idea: The Garden as an ever-changing landscape of birds.

It’s all about the food

We continue along the North Lake road and find two more potential hot spots for birds. A peninsula of land supports a grove of evergreens loaded with cones—a big draw for wintering pine siskins and—if you’re lucky—crossbills. Down the road a bit, you come to an Emergency Call Box. Look past it and you’ll see large junipers growing along the exterior wall near the Garden’s northwest corner. That’s where a very rare Bohemian waxwing, feasting on the juniper berries, was last seen in the Garden.

PHOTO: Egret in flight. — An egret in flight at the Barbara Brown Nature Reserve at the Garden

Walk early, and walk often

We are heading south now, along the Garden’s West Road, past a restored streambed, lush with native plants—a habitat that provides lots of seeds and insects. The best time for birding tends to be the four hours or so following sunrise, so getting up early can have its rewards. Persistence also pays off, Al explains: “It’s a matter of odds. If you look in one spot ten times, you’ll probably see something.” Just then we catch sight of movement in the shrubs. Al first identifies the little bird by the way it waves its tail up and down—an (ahem) telltale sign of the palm warbler, one of the last warblers to head south for the winter.

The Joseph Regenstein, Jr. School of the Chicago Botanic Garden also offers guided bird walks. Learn more about bird walks taking place at the Garden this fall.

Seedheads from native plantings along the restored Skokie River corridor provide ample food for birds.

It ain’t easy—even for the experts

Flocks of goldfinches—displaying olive drab winter plumage—are diving in and out of the tall forbs and grasses of the Dixon Prairie. Niche ecosystems within the prairie provide food and shelter for many different types of birds at different times of the year. Hummingbirds are drawn to the red blooms of royal catchfly (Silene regia) that flower on the dry gravel hills in the summer, while the prairie wetlands attract swamp and other types of sparrows. Turns out sparrows can be tricky to identify, unless—as it happened—one stops to feed on the path in front of you. Al identifies it as a white-crowned sparrow. “For every bird you identify, there are probably five or six you do not get a look at—or you get a lousy look and don’t know what it is,” Al Stokie.

Watch the weather

Shorebirds are drawn to the southwest corner of the Garden, an overflow area for the Skokie River with plenty of muddy shores. “Old Faithful,” a white egret nicknamed by Stokie, comes in for a landing, joining a well-camouflaged green heron and a killdeer, the hardiest of the shorebirds and a late migrator. Most of the sandpipers—Al’s particular interest—have left already. In a flash of movement, the heron fishes a frog out of the water. We witness its slow death through our binoculars, though I have to admit I am still struggling to focus and aim mine. Standing on the sunny, breezy path it’s hard to believe a cold front will be moving through in a few days. That’s likely to bring in a new wave of migratory birds, in this case, sparrows.

Find a mentor

A beginning birder who comes out on his own with a bird book and a pair of binoculars is likely to be overwhelmed, Stokie said. This makes perfect sense to me. Without Al at my side, so much of the experience would have…er…flown right over my head. Take that belted kingfisher back at the Barbara Brown Nature Reserve. While I was still craning around, listening for the rattle, Al had sighted the bird perched in dead branches across the pond. Handing me his binoculars, he asked, “Do you see something, blue?” I saw flashes of blue and white, and the shape of a stocky bird, with a big head.” Okay, it was still slightly blurry, and I had to close one eye to make it out, but I saw it! The moment was recorded for posterity when Al filed his count online. I felt a ridiculous burst of pride when I read the mention, “Adriana’s bird of the day is the kingfisher.”

Join us from 7 to 9 p.m. Friday, November 14, for an Owl Prowl at Ryerson Woods. Click here to register online.

Al looks across the North Lake toward the Fruit & Vegetable Garden for signs of bird activity.

For more information:

Experienced birders David Johnson, Jeffrey Sanders, and Alan Anderson, as well as Jim Steffen, the Garden’s senior ecologist, also helped me gather information for this report. To follow sightings by Al and other local birders, you can go to several websites, including eBird (ebird.org/ebird/places), which designates the Garden as a hot spot, and IBET (groups.yahoo.com/neo/groups/ILbirds/info).