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Chicago winter was brutally cold as usual, but spring is starting to show itself, Chicago-henge happened, and we’re in daylight saving time. This season is a beautiful, blooming time in the second city as the weather gets warmer and the temperatures in the lake and local rivers go up.
City animals instinctively know the drill. Birds are already winging their way back into the region. Black-crowned night herons are returning to Lincoln Park Zoo’s Pritzker Family Children’s Zoo, where the largest colony in Illinois roosts from March to August. Here’s what you’ll see as the season develops all around the city and in your own Chicago neighborhood.
The Birds Are Back!
Last month, waterfowl migration began. Raptors and robust songbird species, including sparrows and swallows, started their return. They start breeding and egg-laying, with the breeding season in full swing into August. You’ll start to see many birds out and about, including migrating ducks and geese but also ones that live in Chicago year-round, like pigeons, ring-necked gulls, and herring gulls.
April is considered by some birders to be the best time of year, because it’s the start or warbler season. Many of the species that overwinter in Central and South American will stop in Chicago in April, either to stay and breed or to rest on their way to breeding grounds to the north. Warblers are largely insectivorous and can be seen foraging in the tree canopy. Some, like palm warblers, stay close to the ground.
In May, a whole bunch of bird species will be winging their way through the Midwest, from ruby-throated hummingbirds and flycatcher species to buntings and warblers. Young birds of many species will start hatching.
What to Do If You Encounter a Baby Bird
Most baby birds fledge, or leave the nest, before they can even fly. If you encounter a baby bird of any species, please leave it alone! Chances are that its parents are nearby and attending to them. Your assistance is not needed, but the thought is much appreciated.
As for the state-endangered black-crowned night herons, many are migratory but some actually live in the Chicago area all year also known as overwintering. As they return to the children’s zoo rookery above the red wolf habitat in late March and April, they start breeding. Then, they’ll start waking early and staying up later to maximize foraging time for themselves and their offspring. The herons nest at the Children’s Zoo, but you’ll also find them at North Pond, Nature Boardwalk, and other urban wetland greenspaces. They will incubate their eggs for about four weeks before the eggs start to hatch. Toward the end of April, expect parts of Pritzker Family Children’s Zoo to close to give the birds privacy.
In May, you’ll start hearing distinct clicking calls from black-crowned night heron young if you pass by the west side of the zoo’s exterior. Mid-month, the heron colony will be at peak abundance. In past years, the colony has numbered more than 700 individuals, both adults and chicks, at this time.
Coexist With Wildlife—Even Red-winged Blackbirds!
May marks peak breeding season for red-winged blackbirds, so these birds will be very active and will defend their territory with flighted attacks. Remember to observe, don’t disturb. Give animals their space. If you are in an area that includes red-winged blackbirds, place an object, such as your hand or a water bottle, vertically on your head. The birds may view this as akin to a rooster comb and be discouraged from approaching. You can also protect your head by wearing a hat.
Reptiles and Amphibians Start to ‘Wake Up’
After they spent the winter brumating, reptiles and amphibians have started to become more active. Among the first to do so is the spring peeper, a small arboreal frog species considered a harbinger of spring—found in Cook County forest preserves and wetlands. They begin mating in the late winter or early spring, and by March, you can hear their distinctive peeping sounds across forested wetlands.
In April, toad species such as Fowler’s toads can be heard at urban ponds and green spaces making their mating calls. And freshwater turtles will start increasing their activity as they emerge from brumation. For some of these local species, like painted turtles, hatchlings from eggs laid the previous year—which overwintered in the nest—will greet the wide world for the first time. In May, expect to see signs of more aquatic frog species, like green frogs and American bullfrogs, and hear their calls. Aquatic turtles will start to mate and dig their nests.
In addition to shaking off the winter sleep, some reptiles and amphibians will start migrating to their breeding grounds in wetlands or nearby swamps and ponds.
Where to See Reptiles and Amphibians at Nature Boardwalk
If you’re walking around South Pond in late spring, you might be able to see painted turtles, pond sliders, and common snapping turtles, along with American bullfrogs and green frogs. Check out the tree branches in the water around Foreman Island, right in the center, to see if you can find some reptilian residents sunning themselves!
Fish Get Active and Start Breeding
Around April, as water temperatures finally start to rise, fish start to become more active. They return to shallower waters to start foraging again. If you’ve walked around Nature Boardwalk recently, you’ll see that they are already very much in evidence.
In May, spawning season begins for the fish species at Nature Boardwalk. Largemouth bass, pumpkinseed, and bluegill males use their fins to create small depressions in the pond substrate, in which females lay tens of thousands of eggs. The eggs are then externally fertilized and guarded by males. It only takes five to 10 days for the eggs of all three species to hatch, so their young will be swimming in abundance by the time summer begins.
Insects Abound
Insects overwinter in different stages of life, from larva all the way to adult. Once temperatures get into the 50-degree range, species that overwinter as adults leave their sheltered spots to find their first meal of the season. Because warmer temperatures are necessary for winged insects to fly, they may not be using their wings to find that meal. They may find sustenance in dead leaves or decaying plant matter, or around plants that are flowering for the first time this year.
Some pollinators, like bumblebees, do not survive the winter, except for one member of the hive—the queen. As temperatures rise and she becomes more active, she will work on finding a new home, forage, and lay eggs that will become adults by summer.
Insects that migrate—or more accurately, their descendants—return. Many of these insects are part of a migration cycle that spans generations, since these animals don’t necessarily live long enough to make the return trip.
Image courtesy of Lead Keeper of Carnivores Jill Dignan.
Monarch Migrations
Most monarch butterflies live from two to five weeks, so there are three or four generations in one summer. The last generation of butterflies in a year experiences changes within their chrysalides as a result of cooling weather and goes into “reproductive diapause.” It is these individuals that migrate to the monarchs’ overwintering spots in Mexico. The butterflies that are part of the “migratory generation” can live as long as nine months. They breed starting in August, but reproduction is delayed until spring.
These same butterflies start flying north again in mid-March, looking for milkweed plants along the way on which to lay their eggs. This generation dies along the route to the north. Once its offspring have hatched and metamorphosed into adults, those newly emerged butterflies are the ones that return to their parents’ original homes.
Plants Bloom
Plants tend to remain dormant until they have been exposed to a certain number of warm days. They also react to the length of time they are exposed to light in a day. Once the weather has met the plant’s warming requirements, they “leaf out,” or flower—and the earlier they do this, the longer the growing season lasts and the better their chances of reproducing. Leafing out involves pumping water into leaves, reducing the sugar, salts, and other compounds that have been insulating their tissues and removing their protection from the cold.
April marks “bud break” for many types of Illinois trees—when a new shoot emerges from a bud during the spring. This synchronizes with the return of many bird species and pollinators that can facilitate pollination and distribute seeds. By May, foliage around the city of Chicago is getting to be full and beautiful, with leaves and other parts of the plant developing and growing. This is also a good development for migrating bird populations. Not only do those trees provide shelter and sustenance, they attract insects, another food source.
Popular flowers that bloom in spring, which you can see at Lincoln Park Zoo and the area, include tulips, daffodils, peonies, and hyacinths. But not all plants flower in spring. Some wait until summer or even autumn. This helps avoid the competition that takes place throughout the spring season, and may make it easier for certain birds and insects to do their work pollinating and dispersing seeds. For example, the zoo’s accredited herbaceous hibiscuses do not bloom until June–August.
Mammalian Baby Boom
March is the birth month for many Illinois mammals. For some smaller mammals, including eastern cottontail rabbits and tree squirrels, the young leave their nests relatively quickly. As long as their eyes are open, they can fend for themselves. The offspring of larger mammals have also developed survival strategies. White-tailed deer fawns may often be found alone, without their mothers; in the first few weeks of life, their stillness and solitude protect them from discovery by predators.
Births continue throughout spring. May is pupping season for bats, which start returning to the state in April; species near Lincoln Park Zoo include big brown bats, eastern red bats, and evening bats. May is also when coyotes start having pups. At Nature Boardwalk, you may see semiaquatic species such as muskrats, American minks, and the American beavers that have already been very active this year. The Urban Wildlife Institute actively monitors all the animals on Nature Boardwalk.
If a Coyote Is Active During the Day, Is It Ill?
Not necessarily! From May through July, coyotes may be more active throughout the day as they search for food for their young. This increased activity makes them more visible to people, though coyotes normally keep their distance from humans. While some assume that an approach by a coyote means they are in distress or potentially sick and therefore dangerous, this is not always true. The approaching coyote may simply have a den with pups nearby, and is peacefully escorting visitors away from the area. In the presence of a coyote, remember to stay calm, keep your distance as best you can, and keep any pets on a short lead.
In coyotes, excessive lethargy, large bald patches on the body, and erratic behavior (such as stumbling and/or lolling of the head) may be signs of illness. If you encounter a coyote with these characteristics, do not approach; only trained individuals should do so. If you think it may pose a danger to humans or pets, call your local animal control service.
