Nature in View – Page 5 – My Chicago Botanic Garden

Black-Capped Chickadees Are Preparing for Winter

Chick-a-dee-dee-dee.

Most people recognize that familiar call of the black-capped chickadee. It’s often heard in late summer and fall as chickadees gather in family groups and small feeding flocks to prepare for the winter.

The chickadee’s song—translated as “Hey, sweetie,” (though you can’t often hear the third syllable)—is reserved for late winter, spring, and summer, when the bird is courting and nesting. Nothing brightens a mid-February day more than when a chickadee sings because to those who hear it, the song signals spring’s arrival.

The black-capped chickadee is the September bird species highlighted by the Forest Preserves of Cook County. Come #birdthepreserves with the FPDCC; there is a free walk at the Garden on September 17, 7:30 to 9 a.m.

The black-capped chickadee is considered a non-migratory species—it can survive the harsh winters of northern Illinois. These birds can lower their body temperature when sleeping at night, which protects them from freezing.

While some birds need to leave the region in fall because insects and other food will soon become difficult to find, chickadees know how to find insect larvae overwintering in tree bark (although flocks of chickadees do make small geographic movements, depending on food availability in colder months).

They also stash seeds to eat later, and unlike squirrels, they remember where they put them. Chickadees eat berries and animal fat in winter, and they readily come to feeders feasting on seeds and suet. Supplemental food, especially sunflower seed from feeders has been shown to help these little balls of feather and hollow bones survive when it gets really cold and wet outside. Those who feed birds can observe an interesting behavior in chickadees—they form a hierarchy, meaning the top chickadee gets to eat at the feeder first—it snatches a seed and leaves, then the second in command gets its turn.

PHOTO: A chickadee enjoys a plentiful and tasty treat in early February: berries. — A black-capped chickadee enjoys a plentiful and tasty treat in early February: berries.

In February, chickadees begin singing and looking for a cavity hole in which to nest—and there’s a wide variety of homes they’ll find suitable. They’ll choose abandoned woodpecker cavities and man-made nest boxes, or excavate their own small, natural cavities. Chickadees will nest in rotted, old wooden fence posts and abandoned mailboxes, and a pair once built a nest in an old shoe hanging from a line.

The female builds a cup-shaped nest with moss for the foundation, lining it with rabbit fur or other soft material. She has one brood each year, laying an average of seven to eight eggs. After 12 days of incubation, the young hatch, then remain in the nest for another 16 days. When they fledge, they continue to follow their parents, calling and begging for food. Come winter, they travel in small feeding groups, often with nuthatches, titmice, and other small songbirds.

West Nile, which came to the U.S. about 17 years ago, likely may not have affected black-capped chickadees as much as some thought, according to a recent study.

Though people were seeing fewer chickadees in their backyards and in woodlands when the virus came to the region, a 2015 study showed that overall black-capped chickadee numbers have not been affected by the mosquito-borne disease, especially compared with other species. Studies will continue on how the virus is affecting bird populations—but one thing is for certain—when the virus struck, it reminded humans not to take for granted the common birds they enjoy. And the black-capped chickadee is certainly a species that humans enjoy watching and hearing.

Ruby-throated hummingbird migration begins

In August, when the jewelweed and cardinal flowers bloom, the ruby-throated hummingbird is migrating. It’s perfect timing, because the hummingbirds get energy for their journey southward by sipping nectar from the blossoms of these plants native to northern Illinois.

The ruby-throated hummingbird is the August bird species highlighted by the Forest Preserves of Cook County. Come #birdthepreserves with the FPDCC; there are two free upcoming walks at the Garden.

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

The ruby-throat is the only hummingbird to breed in eastern North America, and these tiny jewels are somewhat common nesters in Cook County woodlands. They become more numerous in late summer and fall, as those that nested farther north pass through on their way to their winter homes in Mexico and Central America.

The ruby-throated hummingbird (Archilochus colubris) wears emerald green on its back and crown, and in good light, the male reveals an iridescent red throat. (During fall migration, you’ll see males as well as females and young, both of which lack the ruby throat.)

They return to Illinois in April and May, seeking nectar from early blooming trees and shrubs as well as insects and spiders.

It’s at this time you might get lucky enough to observe the courting male as he flies in a U-shape and also buzzes in front of a perched female. Buzzes? Yes! Hummingbirds aren’t silent—you can hear their wings buzz and vocalizations from their throats when they’re defending feeding territory or seeking a mate.

The female builds a thimble-sized cup nest on a horizontal branch, adding grasses and spider webs, lining it with plant down and then covering the outside with lichens and dead leaves. The young hatch in about 15 days, and remain in the nest for another 20 days or so as the female brings them insects.

An aerial wonder, the ruby-throated hummingbird, can beat its wings 53 times per second, and can fly backward and upside down.

You can attract ruby-throated hummingbirds to your yard by planting the flowers they love—tubular and brightly colored in red hues—and by putting up feeders. Hummingbirds are fun to watch at feeders as they have spats in flight trying to hoard the food to themselves.

To make hummingbird food, add ¼ cup white sugar to 1 cup boiled distilled water. Stir to dissolve, then cool before you put it into the feeder. It’s not necessary to put red food coloring in the water. Use a red feeder to attract the hummers. Hang out of direct sunlight, and clean and refill often.

Most ruby-throated hummingbirds are gone by the end of October in this area. You can put your feeders back up in April when they return.

The Nocturnal Nuance of Moths

With more than 1,850 known species of moths in the state of Illinois—more than ten times the diversity of butterflies—it is a real adventure sampling the moth species inhabiting the McDonald Woods at the Chicago Botanic Garden.

Using a combination of light and bait traps along with visual searches, I have been investigating the diversity of moth species found in the restored portions of our oak woodland. Moths are removed from the traps and then photographed before being released back to the woodland.

PHOTO: Ctenucha virginica (Virginia Ctenucha) moth. — The metallic scales of *Ctenucha virginica* (Virginia Ctenucha moth) are striking—even its wings have a metallic sheen.

My interest in moths stems from the fact that many of the species are dependent on one or just a few native plant species for their survival, and as a result, may serve as valuable indicators of the health of our recovering, once-degraded oak woodland. The larval stages—the caterpillars—primarily feed on the roots, stems, and leaves of the plants. Adult moth species are very important pollinators. White-flowered and night-fragrant plant species are often what they seek. There are day-flying moths also, like some of the hawk moths (which are often mistaken for hummingbirds) that are seen visiting a variety of flowers in full daylight. Moths are also a tremendously important part of the food chain. Entomologist Doug Tallamy tabulated the number of caterpillars that were utilized to support one nest of black-capped chickadees and found that they consumed between 6,000 and 9,000 caterpillars, most of which were moth species. Adding even a few native plant species to your yard can benefit a multitude of these valuable invertebrates.

PHOTO: Smerinthus jamaicensis (Twin-spotted sphinx moth). — *Smerinthus jamaicensis* (Twin-spotted sphinx moth)

PHOTO: Plusia contexta (Connected looper moth). — *Plusia contexta* (Connected looper moth)

PHOTO: Ponometia erastrioides (Small bird-dropping moth). — *Ponometia erastrioides* (Small bird-dropping moth)

PHOTO: Plagodis phlogosaria (Straight-lined Plagodis moth). — *Plagodis phlogosaria* (Straight-lined Plagodis moth)

It is a never-ending surprise to see what new species will show up each time traps are placed.

Some species are so small (usually referred to by lepidopterists as micromoths) that most people would pass them off as gnats or pesky flies. Some micromoths are only 3-4 millimeters long. One in particular I like to refer to as the “Nemo” moth, as in Finding Nemo. I gave this species that name because its colorful pattern reminds me of a clown fish.

PHOTO: A cryptically-colored Noctua pronuba (Large yellow underwing moth). — A cryptically colored *Noctua pronuba* (Large yellow underwing moth)

At the other end of the spectrum are the moth species that are quite large. The giant silkworm moths, like the luna and Cecropia moths, have a wingspan of more than 140 millimeters. Starting in mid-July and going through September, a group of medium to large moths known as underwing moths starts appearing in the woods. These delta-shaped species are usually very cryptically colored on their forewing and brightly and starkly colored on their hind wing. The cryptic forewing allows them to blend in with the tree trunks they are resting on; the hindwing only becomes visible when they spread their wings to fly. It is thought to be a distraction or scare tactic to foil predators.

Although there is a subtle nuance of shapes, colors, and textures that distinguish many species, there are also those that are in-your-face with shockingly bright colors, metallic ornamentation, stark patterns, and jagged ridges of scales—much like a mountain range on six legs—that never fail to impress me. The looper moths are one good example. Many have stigmas (distinctive white patches and scrolling) on the surface of the wing and spectacular assortments of peaks, crowns, and ridges of scales on the thorax and inner edges of the wings. The scale patterns most likely evolved to break up the silhouette of the moth to make it less visible. One of the hooded owlet moths has a tall patch of scales on its thorax that looks like a witches hat when erect, but it can also be laid down over the moths head to make it look like a broken-off stick.

PHOTO: Leucania pseudargyria (False wainscot moth). — *Leucania pseudargyria* (False wainscot moth)

In general, there is a new group of species that emerges about every two weeks during the year, with midsummer being the peak for species and abundance. Many moth species have relatively short flight periods and can only be seen at certain times of the year, but some have multiple broods that show up several times during the year. When I show some of these moths to colleagues, they almost always say, “I never knew these things existed.”

Under the cover of darkness, there is a world of beauty and fascination fluttering silently among the trees. It makes me wonder if the full moon doesn’t show up once a month just to shed a little light on the show, just so we don’t miss it completely.

Osprey: Fish-eater returns as breeder in Cook County

Several decades ago, an osprey would be a rare—if not impossible—sight in Cook County in the summer. But now, thanks to the ban on certain pesticides (including DDT), and the creation of osprey nesting platforms, the fish-eating bird is breeding again in local forest preserves.

The osprey looks somewhat like an adult bald eagle, but doesn’t have the eagle’s full white head or tail. Instead, it has a broad brown band through the eye, a brown back, and white belly. An osprey flies with a crook in its wings. Immature bald eagles, with their mottled black and white plumage, can easily be mistaken for ospreys. In summer, visitors can watch an osprey (Pandion haliaetus)—with its 6-foot wingspan—soar above a lake, then plunge in to snatch a meal with its talons to bring to its young.

Once endangered in Illinois, the osprey disappeared as a breeding bird from Illinois about 60 years ago. Scientists think, as with the bald eagle, that when the osprey ingested certain pesticides, the chemicals caused its eggs to thin and crumble during brooding. After DDT was banned, state biologists hoped the osprey would return to breed in Illinois. But the bird needed some help, including cleaning up local waterways and providing nesting areas.

In the 1990s, Cook County Forest Preserves officials, following the lead of biologists in other states, began erecting osprey nesting platforms—40-inch-wide platforms atop 50-foot-tall posts—in the preserves, hoping the ospreys would use them to nest.

It worked. The tall structures gave the ospreys a 360-degree view of their surroundings, something scientists say the birds need when choosing a nesting spot. Today, at least a dozen osprey pairs breed in Cook County, with several more in other nearby counties.

This year, the Chicago Botanic Garden installed an osprey nesting platform, and is waiting to see if a pair will find it to their liking.

According to officials of the Cook County Forest Preserves, 12 osprey pairs bred on man-made platforms in the county in 2014, including at Long John Slough at the Little Red Schoolhouse in Willow Springs. A pair of osprey tending to their nest atop a platform was photographed at Saganashkee Slough in the Palos Preserves this year by Wes Serafin, a long-time proponent of helping ospreys return as a breeding species to Cook County.

PHOTO: An osprey keeps a tight grip on lunch. — An osprey keeps a tight grip on lunch.
Photo © Carol Freeman

The ospreys return in April, often to the same platform they used the previous year. They build a nest of sticks atop the platform, adding new ones each year. The female lays three to four eggs, which hatch in about 38 days. While she broods, the male fiercely defends their territory and brings food to his mate. The young remain in the nest for about two months, begging constantly for food. Then they take their first flights off the platform.

Watching an osprey grab a meal can be fascinating. The bird appears as if it is going to plunge head-first into the water, but then it straightens its head and grasps the fish with its talons. Two forward-facing and two backward-facing toes have sharp spines that enable the bird to clutch the fish. Occasionally an osprey will grab a fish too heavy for it to carry, in which case the osprey might drop it, and try for another meal.

The osprey that nest in northern Illinois in summer spend winters in Florida, Mexico, and South America.

The Illinois Department of Natural Resources is now in the fourth year of their program designed to bring more osprey to the state to increase the number of breeding pairs.

The osprey is the July bird species highlighted by the Forest Preserves of Cook County. Come #birdthepreserves with the FPDCC; view the list of upcoming events for free events near you.

Prairie Blooms Beckon

It’s time for a visit to the Dixon Prairie to savor late spring flowers and the pollinators visiting these plants.

White wild indigo (Baptisia alba var. macrophylla) — White wild indigo *(Baptisia alba* var. *macrophylla)*

A standout plant, looking almost like a small shrub, is white wild indigo (Baptisia alba). This is the white-flowered cousin to blue wild indigo (Baptisia australis); this plant, not native to the Chicago region, was historically a source for blue dye. Both species are in the pea family. Many prairie plants belong to the pea family; other important families of the prairie are sunflower, sedge, and grass. Queen and worker bumblebees primarily pollinate white wild indigo. Their large size allows them to push down the lower part of the flower (the keel) and thus expose the pollen producing anthers.

A rich palette of blue flowering plants from the Ohio spiderwort (Tradescantia ohiensis) surrounds the white wild indigo plants. A variety of bees and butterflies might be seen visiting these plants, bumblebees being the primary pollinator. Butterflies, in their quest for nectar, will not be rewarded for their visit, however, since Ohio spiderwort doesn’t have nectar.

Spiderwort (Tradescantia 'Sweet Kate') and coneflowers bloom on the Prairie. — Spiderwort *(Tradescantia* ‘Sweet Kate’) and coneflowers bloom on the prairie.

The prairie also currently hosts numbers of white tubular flowers, foxglove beardtongue (Penstemon digitalis). On the lower half of the flower is a large hairy sterile stamen (the part of the flower that produces pollen); perhaps this feature is the origin of the plant’s common name. Pollinators, primarily bees, must work their way past this sterile stamen to reach pollen. This effort increases the likelihood of pollen being deposited on the stigma, the organ that is receptive to pollen. Those willing to observe these flowers for a while might be rewarded with witnessing some territory defending. The male of an introduced bee, the European wool carder bee, with sharp spines on their abdomens, will attack other males who come in the vicinity of the female when she is foraging for nectar.

Just opening on the gravel hill prairie is the pale coneflower (Echinacea pallida). The narrower leaves of this plant distinguish it from the commonly planted purple coneflower (Echinacea purpurea) (sometimes called broad-leaved coneflower). Like other members of the sunflower or aster family, the coneflower has what appears to be a singular flower but is actually a head of many flowers. This species has what are called ray and disc flowers. Some sunflower plants have only disc flowers while others, such as dandelions, only ray flowers. This plant is a preferred nectar plant of both bees and butterflies.

Moving into summer, this palette will change and reveal a new tapestry of grasses and wildflowers. To witness the full bounty of the prairie, a prairie visit should be a weekly affair.