spring – Discover-Nature

Spring Migration

Meteorological spring starts Sunday, and we are already starting to hear the calls of early migratory birds, heading north from southern wintering grounds, working to establish territory their among the best nesting sites available.

Red-winged blackbird, Agelaius phoeniceus, singing by Rhododendrites, May 2023

Some birds, including red-winged blackbirds, Agelaius phoeniceus, get their cue to start spring migration as temperatures get warmer. These species head to prairies, forests, and wetlands to claim a location they can protect, call for a mate, and establish a nesting site with good protection and food sources. Other birds, including many warbler species, return in spring when daylight hours lengthen. Generally flying at night, they use star positions and the Earth’s magnet field to guide them. If nights are stormy or heavily overcast, early morning may find hundreds of them waiting in fields for clear skies. Birds may also stop for a day or two in areas located on the southern shores of any large body of water to rest and feed before crossing.

Red-winged blackbird, *Agelaius phoeniceus,* flock at sunset by Jerry Segraves

Bird species around the world generally follow established flyways, established routes over specific locations between their southern and northern territories. Many migration routes do not follow a straight path. Some species have historical stopover or feeding locations that provide a rest point along the way. Other species may not be able to cross a mountain range; or a large body of water can act as a barrier for land birds, but may be a required food source for wetland birds.

Arctic tern, *Sterna paradisaea*, adult & juvenile by Charles J Sharp, Aug 2025

Arctic tern, *Sterna paradisaea*, in flight by Charles J Sharp, Aug 2025

Long distance migration routes are most common for birds wintering in subtropical and tropical areas and breeding in the northern hemisphere. Long migrations in the southern hemisphere are far less common because there is less land near the South Pole to support breeding activities. The record holder for migration distance is the Arctic tern, Sterna paradisaea, overwintering in Antarctica and breeding in Arctic locations, a round trip between 30,000 and 55,000 miles. Some shorter migrations are between upper and lower altitudes in mountainous regions.

Penguin migration map by Fred Cooke
& Jenni Bruce, Aug 2011

Dusky grouse male, *Dendragapus obscurus*, displaying by US NPS

Most birds migrate in flocks, which reduces the energy needed to fly long distances and provides added protection against predators. Penguins migrate without flying. Most penguin species swim between locations, covering up to 1,000 miles round trip. A few species cover long distances on foot, including dusky grouse, Dendragapus obscurus, in the Rocky Mountains which walk from lower to higher elevations. However, a flock may encounter unfavorable weather or flying conditions that causes a large number of birds to stall in one location, introducing other risks including depleted food sources and predation by land-based animals.

At the Jurica-Suchy Nature Museum, we host a nature walk every other week to observe changes in our campus including the birds that are moving through the area. There are many birding groups worldwide that provide opportunities to observe and learn about migratory birds in every location. Consider joining a group, or take your own bird walk as we have clear days and warming temperatures and see who’s on the move in your area.

Forest Floor

Two main types of forests grow in the regions between the tropics and the poles, deciduous forest and coniferous forest. A majority of energy from sunlight is captured by the canopy vegetation, with little leftover to reach the forest floor. And yet, the lowest level of the forest has an abundance of food and organisms.

Deciduous species are mainly hardwoods including oak, birch, maple, ash, beech, and hickory. These trees have leaves that are broad and flat, designed to catch sunlight. Conifer forests are made up mostly of softwood tree species from the pine and fir families. Most conifers have leaves that are long, thin, and needle-like, a compact form of leaf that is often waxy and designed to withstand the rigors of an environment that is cold and dry for long periods.

^{Green ash tree leaf in summer & autumn by Alain de Maximy}

Chlorophyll is a chemical that is synthesized by plants and gives leaves and needles their characteristic green color. Plants use chlorophyll to absorb energy from sunlight and use that energy to power the process of photosynthesis which creates carbohydrates, providing food for the rest of the plant. Senescence, the process that occurs when a plant stops making chlorophyll, happens as seasons change and day length shortens while temperatures fall. As chlorophyll is removed, leaves and needles lose their green hues and show their underlying colors of browns, reds, and oranges even as they die and fall to the forest floor.

^{Black beetle on forest floor by Undefined, Getty Images; Forest floor fungi cluster in Autumn woods by Vladimir Srajber, Pexels; Springtail on fallen log by Henrik L, Getty Images; Lush moss covering the forest floor by Doina Gherban}

Fallen leaves create a thick layer of litter, broken down by a rich variety of decomposers including mosses, fungi, insects, and other invertebrates. Decaying vegetation releases nutrients back into the soil to be used once more as food for other forest plants. The annual leaf fall adds an estimated 2,600 pounds of vegetation per acre back into forest habitats worldwide.

In deciduous forests, all of the leaves typically fall in late autumn opening up the forest floor to sunlight in early spring. A group of plants known as spring ephemerals take advantage of this sunlight to quickly flower, bloom, and reproduce before leaves re-appear and shade once more rules the forest floor. In conifer forests, where shade is ever-present, flora is restricted to shade-loving species such as ferns and fungi. In addition, fir and pine tree needles are high in acid content and their leaf litter is only broken down by a relatively few fungi species over long periods of time.

All forest floors are rich with many organisms present throughout the year. Invertebrates including insects, fungi, and small mammals spend their entire lives living in the leaf litter. Detritus from leaf fall provides food and nutrients throughout the year to the plants and other organisms living in these wonderful habitats. As you walk the forests, no matter what the season, think about all of the life going on around you each day on the rich woodland floor.

Jurica-Suchy Nature Museum Updates

The Jurica-Suchy Nature Museum will be open all summer, and you can find our current hours or make a reservation by using the QR code below or accessing our website at ben.edu/museum. We continue to create new exhibits and resources for visitors. Many of these resources are highlighted below…

The Discovery Box Loan Program provides specimens and educational materials covering a wide range of species and nature topics. This summer we are updating and adding duplicate boxes for many topics. We are also a repository for IDNR Resource Trunks. New boxes recently added share information on birds and insects.

Nature Rx wellness walks are offered every semester for anyone who would like to learn about and enjoy nature as we find it in the woods and areas around Lake Benedictine on the west side of campus. Come out to enjoy a 45 minute walk, narrated by an Illinois master naturalist, and see what is in bloom or who is inhabiting our woods today!

Nature Doodlers, the museum’s own nature journaling club, meets once a month at the museum at 10:00am on the last Saturday of the month. We have a 30-minute presentation on the monthly topic with time for discussion and practice afterwards. Draw from subject specimens in our collections, or take it outside on campus. A beginner’s nature journaling kit is free for all newcomers, but feel free to bring your own supplies. In June we are exploring plants, leaves, and basic botany, while in July we will be observing insects, arachnids and other arthropods. Come on out to learn, observe, and record your observations.

Next weekend, the museum director and volunteers will be out at the Morton Arboretum’s annual Nature Play for All Weekend. Bring your family out to hike and explore seeds, pond life, art, and more in the Arboretum’s Children’s Garden.

There will be more events coming throughout the year including our annual Life In The Pond turtle day in September and Creepy Critters – a Halloween wildlife celebration in October. More changes are also coming to our website, Discover-Nature.org with additional resource pages and museum information. You can sign up for our bi-monthly blog at https://discover-nature.org/

Sounds of Spring

Thunder and heavy rain, soft rain and light wind, birds in the early morning, frogs in the evening, and maybe a coyote howl deep into the night are some of the sounds of spring. As cold temperatures ease into summer highs, walks through natural areas tend to be filled with many sights as well as opportunities to learn by being quiet and listening closely.

Calls and songs are used by many species for a variety of purposes. Thousands of birds are migrating through the area, especially on clear evenings, and calls help to keep birds together and establish who is the flight leader. Year-round species are re-establishing territories, using calls to warn intruders to stay away or warn family members of approaching threats. Frog species in particular are calling during evenings to find a mate, lay eggs, and begin the establishment of the next generation.

There are dozens of species active at this time of year, and as we have been taking nature walks on campus the last few days, here are some of the wildlife we are listening to (click on each picture to hear their call)…

^{Yellow-rumped warbler, Setophaga coronata, Mirceax, Getty Images}

Yellow-rumped warbler, Setophaga coronata, by Valerie Heemstra, 2024

^{Red-winged blackbird, Agelaius phoeniceus, by KenCanning, Getty Images Signature}

Red-winged blackbird, Agelaius phoeniceus, by Thomas Ryder Payne, 2022

^{Palm warbler, Setophaga palmarum, by Irving A. Gaffney, Getty Images}

Palm warbler, Setophaga palmarum, by Christopher McPherson, 2021

^{Northern waterthrush, Parkesia noveboracensis, by Carol Hamilton, Getty Images}

Northern waterthrush, Parkesia noveboracensis, by Lance A.M. Benner2017

^{Northern Parula, Setophaga americana, by Neil Bowman, Getty Images}

Northern Parula, Setophaga americana, by Richard E. Webster, 2023

^{Chipping sparrow, Spizella passerina, by Irving A. Gaffney, Getty Images}

Chipping sparrow, Spizella passerina, by David Tattersley, 2023

^{Blue-headed vireo, Vireo solitarius, Mirceax, Getty Images}

Blue-headed vireo, Vireo solitarius, by Thomas Magarian, 2024

^{Blue Jay, Cyanocitta cristata, by Miguel Opacic, Getty Images}

Blue Jay, Cyanocitta cristata, Sue Riffe, 2024

Bird songs have a structure and rhythm, and are repeated often to attract a mate, ward off rivals, or bond with a family member. Other calls give warning that danger is near, keep flocks together in flight, or create a pair bond, often between mother and chick.

Frogs and toads are mating and laying eggs in area ponds. Each species has its own distinctive call, used by the males to attract a mate, warn of potential danger, establish a territory, or to signal distress. Frog species being heard around campus at this time include the following (click on each picture to hear their call)…

^{American Toad, Anaxyrus americanus, by Mshake, Getty Images}

American Toad, Anaxyrus americanus, by Thomas Margarian, 2024

^{Boreal chorus frog, Pseudacris maculata, by Derwyn, Getty Images}

Boreal chorus frog, Pseudacris maculata, by Thomas Margarian, 2016

^{Spring peeper, Pseudacris crucifer by HuntImages, Getty Images Signature}

Spring peeper, Pseudacris crucifer by Paul Marvin, 2012

^{Northern Leopard Frog, Lithobates pipiens, by Jennifer Seeman, Getty Images}

Northern Leopard Frog, Lithobates pipiens, by Paul Marvin, 2015

Sometimes, coyote can be heard when walking in woodlands around campus late in the evening. There are a lot of different calls used by these canines to provide information to other individuals. You can listen below to a bark used to indicate a threat, a social call establishing an individual’s location, a begging call from a young one, and a howl audible over long distances to announce one’s presence. Other calls may include a woof to signal a low intensity threat, a yip to claim territory, a growl to threaten another animal, and a whine or yelp to show subservience to a more dominant individual.

^{Coyote, Canis latrans, barking by TakenPix, Getty Images}

Coyote, Canis latrans, bark by Paul Marvin, 2018

^{Coyote, Canis latrans, begging, by Keith Szafranski, Getty Images Signature}

Coyote, Canis latrans, begging call by Matthew L. Brady, 2025

^{Coyote, Canis latrans, social interaction by Michel Viard, Getty Images}

Coyote, Canis latrans, social call by Flor Sangermano, 2023

^{Coyote, Canis latrans, howling, by Keith Szafranski, Getty Images Signature}

Coyote, Canis latrans, howl by Paul Marvin, 2012

Additional wildlife sounds can be heard on campus around Lake Benedictine or in nearby forest preserves. Get out for a walk and be sure to listen throughout the day for bird species, and into the evening hours for frogs, toads, and coyotes.

Natives In Bloom

Spring has arrived in northern Illinois with warming temperatures and spring rains. At this time of year, we can observe many of the early ephemerals in bloom. Many of these species only bloom for a short period before the flowers are gone, but the plants continue to grow and put forth fruits and seeds before dying back altogether until next spring. Let’s take a look at what is blooming right now in our area.

^{Bloodroot, Sanguinaria canadensis, by DonArnold, 2025}

^{Bloodroot, Sanguinaria canadensis, colony by DonArnold, 2025}

Bloodroot, Sanguinaria canadensis, is one of the earliest plants to bloom as soon as warmer temperatures stabilize. It is a perennial that grows up to a foot tall. Each leaf unfolds to reveal a single white flower with bright yellow anthers. Each flower blooms for only one to two days, and the entire colony of plants last about two weeks.

^{Sharp-lobed hepatica, Hepatica nobilis acuta, by DonArnold, 2025}

Sharp-lobed hepatica, Hepatica nobilis acuta, a member of the buttercup family, reaches only a few inches in height. Flowers are white, pink, or blue, clustered in tufts of several blooms. They like woodlands and rocky bluffs, and flowers persist for two to three weeks.

^{Celandine poppy, Stylophorum diphyllum, by DonArnold, 2025}

Celandine poppy, Stylophorum diphyllum, is a taller plant between 12″ and 18″ in height. Each stem bursts forth in two to four golden yellow flowers. If cut open, the sap is an orangish-yellow color. After about three weeks, flowers die back and an inch long, ovoid seed capsule grows for several weeks before releasing numerous seeds upon splitting open.

^{Virginia bluebells, Mertensia virginica, by DonArnold, 2021}

Virginia bluebells, Mertensia virginica, stands tall at one to two feet. Pale pink or blue flower buds open to light blue tubular flowers. Blooms last about three weeks and make a dazzling display when plants are observed clustered over a large space in many shaded woodlands throughout the area.

^{Shooting Star, Dodecatheon meadia, by DonArnold, 2025}

Shooting star, Dodecatheon meadia, is a group of 17 subspecies of flowering plants found throughout North America and Siberia. Standing up to 18″ tall, a cluster of eight to twenty purple, pink, or white flowers with yellow stamens hang from the top of each stalk.

^{Spring Beauty, Claytonia virginica, by DonArnold, 2021}

Spring beauty flowers, Claytonia virginica, open on warm, sunny days but remain closed when clouds or cool breezes are present. They bloom for one to two months in late spring and like dappled sunlit areas. White blooms with pink lining give off a pleasant floral scent.

^{White trout lily, Erythronium albidum by DonArnold, 2021}

^{White Trout Lily bloom, Erythronium albidum, by DonArnold, 2021}

White trout lily, Erythronium albidum, grows in large patches of four to six inch high plants with bright white blooms that stand out among dark green leaves mottled with brown markings. The flower nods from a short stalk and blooms for about two weeks in late spring.

^{Cutleaf toothwort, Cardamine concatenata, by DonArnold, 2021}

Cutleaf toothwort, Cardamine concatenata, stands about ten inches tall with large-lobed, toothed leaves. Many small white flowers with yellow anthers bloom above the leaves for about two weeks.

^{Mayapple, Podophyllum peltatum, by DonArnold, 2021}

Mayapple, Podophyllum peltatum, stands up to eighteen inches tall. Infertile plants produce one leaf on a single stalk. Fertile plants have two leaves on petioles branching from the stalk, with a nodding flower growing from the juncture of the petioles. Flowers are pale white with a yellow or greenish middle.

^{Prairie trillium, Trillium recurvatum recurvatum, by Karly Tuminello}

^{Large-flowered trillium, Trillium grandiflorum, by СССР, May 2019}

Trillium grows in prairie and woodland habitats. There are seven recognized species, and two of the ones that you are most likely to observe in our area are large-flowered trillium, Trillium grandiflorum, and prairie trillium, Trillium recurvatum recurvatum. Large-flowered trillium is declining in population, preferring swamps or wet soil areas, which are also declining as development expands and destroys these habitats. Prairie trillium prefers open woodlands dominated by oak, hickory, and maple species. All species of trillium are notable for their structure consisting of three leaves and flowers with three petals.

^{Dutchmans Breeches, Dicentra cucullaria, by DonArnold, 2025}

^{Dutchmans Breeches, Dicentra cucullaria, by DonArnold, 2021}

Dutchman’s breeches, Dicentra cucullaria, stands about six inches tall, with a white flower shaped like a pair of pants hung upside-down from a pedicel. These plants are found in undisturbed woodlands, especially along ledges and ravines throughout Illinois.

^{Eastern redbud, Cercis canadensis, by Greg Hume, Apr 2005}

^{Eastern redbud, Cercis canadensis, buds up close by Greg Hume, Apr 2005}

Eastern redbud, Cercis canadensis, is a small tree or large shrub, growing up to thirty feet high. The bark is dark and smooth, and twigs are slender with a zig-zag appearance. Flowers bloom in mid to late spring and form small, vivid rose-colored bunches.

^{Serviceberry, Amalanchier sp, by DonArnold, 2025}

Amalanchier is a genus that includes about two dozen varieties of small trees or shrubs. These are known by several different common names including shadwood, serviceberry, sugarplum, saskatoon, and others. They bloom for short periods in late spring, displaying clusters of four to twenty white flowers. Small red berries grow in mid to late summer, but do not last long since they are a favorite food source for both birds and small mammals.

Getting out for a walk to your favorite prairie or woodland habitat over the next few weeks will provide the opportunity to observe many of these plants while they are in bloom, including our own woodland trail around Lake Benedictine here at the Jurica-Suchy Nature Museum.

Great Horned Owls

The great-horned owl, Bubo virginianus, is native to much of the Americas, including most of North America and Central America and about half of South America. It is the second heaviest owl in North America, right behind the snowy owl, Bubo scandiacus, weighing up to five-and-a-half pounds with a wingspan between three and five feet.

^{Great-horned owl, Bubo virginianus, by Andy Reago&Chrissy McClareen, Aug 2012}

^{Range and distribution of Great-Horned Owl, Bubo virginianus by BirdLife International, 2014}

Feathers cover the entire body, including their feet, and are varying shades of browns and grays. Their backs and heads are mottled or barred in several patches. This coloration, especially when coupled with mostly nocturnal activities, provides excellent camouflage. Their ‘horns’ are actually feathers sticking upwards on either side of their heads. These are called plumicorns, but their function is not well understood. The feather structure of the wing allows owls to fly silently and includes a serrated leading edge to disrupt turbulence and softer feathers behind to help deaden sound.

^{Great horned owl plumicorns by Jean-pol Grandmont, Aug 2013}

^{Great horned owl wing structure by Peter K. Burian, Aug 2015}

The owl’s ears are covered by feathers, but are not symmetrical with one being higher on the side of the head than the other. This arrangement provides the owl with the ability to triangulate sounds and precisely locate prey in the dark or when prey is hidden, such as when an animal is moving about under a layer of snow. Their flattened face, shaped as a round disc, also helps to direct sound to their ears. Like all owls, their eyes are fixed in the sockets, but the bird can swivel its head almost 180° to either side allowing it to see in all directions.

^{Great horned owl talons by Curtis Bouvier, May 2010}

Great horned owls hunt from a perch, observing the area below them before diving swiftly and silently from far above. Their diet consists of small mammals, birds, amphibians, and a variety of snakes. Their talons are powerful and deadly, with a grip comparable to much larger birds such as golden eagles. Most prey is killed by being pierced or crushed in the talons. Owls may hunt and kill for more than their immediate needs and will cache their kills for future meals.

Great horned owls are not migratory. When an owl is ready to mate, courtship occurs in late fall and pairs mate for life, establishing a territory together in which they will live their entire lives. Most territorial defense is through hooting at a transgressor, but rare physical confrontations have been observed. If an owl cannot establish its own territory, it will live in silence among the fringes of other territories.

^{Great-horned owl juveniles, Bubo virginianus, by Alan Vernon, Jun 2010}

^{Great horned owl female & juvenile on nest by John Kees, Apr 2012}

Males are responsible for picking a nest site, almost always taking over a nest constructed by another species. Mated pairs breed once every two to three years, laying from one to six eggs. Egg laying occurs between late February and early April. The female alone incubates the eggs, never leaving the nest, while the male hunts and brings her food. After about 33 days, the eggs hatch. Young owls will start to fly after seven weeks, but take a full month or more to become proficient.

^{Great horned owl calling, Bubo virginianus, by Michael & Katie LaTour, Jan 2019 (at 0:02, 0:10)}

^{Great-horned owl pair calling by Bushman, Dec 2013 (at 0:18, 0:41, 0:51, 1:22)}

Owls are more often heard than seen. Although the females are larger than males, females have a smaller voice box and thus a higher pitched hooting call ending with a slight rising note. Juveniles can make hissing or screeching sounds and are often misidentified as barn owls, Tyto furcata.

You can learn more about these magnificent birds at the Jurica-Suchy Nature Museum. Make a reservation to come see us by visiting our website at: https://ben.edu/campus-links/jurica-suchy-nature-museum/ (click on Register to Visit the Museum).

Bird Song

As spring approaches, many bird species will be migrating across the country from warm winter sites back to summer nesting areas to mate and raise young. For many bird watchers, a favorite activity is to identify birds by their songs. Songbirds have an organ called the syrinx that produces the lyrical notes we can listen to. Birds may produce one or more notes at a time creating complex calls and melodies. Some of these songs are used to attract a mate, or to identify itself to another family member, or as calls of warning about any approaching danger. Night traveling species may use calls to keep the flock together while flying, but most calls are heard throughout daylight hours.

In the upper Midwest, in prairie and wetland areas, the first migrators in early March will include ruby-crowned kinglets, blue-winged teals, loggerhead shrikes, upland sandpipers, and eastern bluebirds. As night time temperatures become warmer and stable, summer tanagers, Baltimore orioles, and up to 35 warbler species will begin moving through this area. Some species to watch for in northern Illinois are American white pelicans, common loons, Northern pintail ducks, and yellow-bellied sapsuckers.

You can find many excellent observation spots in your area by searching online for “spring birding hotspots in your area”. Another favorite forecasting site to follow migrating bird groups is the University of Cornell’s BirdCast Project website.

American white pelican, Pelecanus erythrorhynchos, by Manjith Kainickara, Nov 2010

Call from a young chick by Andrew Spencer, XC36292

Baltimore oriole, Icterus galbula, by Tony Castro, May 2013

Alarm call by Joost van Bruggen, XC864040

Call by Gus Mueller, May 2007

Blue-winged teal, Spatula discors , by Alan D. Wilson

Call by Jonathon Jongsma

Common loon, Gavia immer, by John Picken, Jul 2011

Tremolo call by Darwin Long, Apr 2006

Eastern bluebird, Sialia sialis, by Sandysphotos2009, Apr 2010

Call by Jonathon Jongsma, Jun 2011

Loggerhead shrike, Lanius ludovicianus, by Jeffrey Gammon, Dec 2020

Alarm call by Bobby Wilcox, XC418584

Call by Ed Pandolfino, XC455607

Northern pintail, Anas acuta, by J.M. Garg, Jun 2007

Call by Paul Driver, Feb 2012

Pied-billed grebe, Podilymbus podiceps, by Mdf, 2005

Begging call by José Dellacasa Bravo, XC946741

Nocturnal flight call by David Tattersley, XC811994

Pair contact call by Richard E. Webster, XC971465

Ruby-crowned kinglet, Regulus calendula, by Tony Castro, Jun 2019

Call by Christian Kerihuel, XC814137

Sandhill crane, Grus canadensis, by Jeffery Gammon, Jan 2017

Call by National Park Service, Jan 2004

Left: Summer Tanager female, Piranga rubra, by Gonzalo Zepeda Martinez, Jan 2016

Right: Summer Tanager male, Piranga rubra, by Charles J. Sharp, Feb 2023

Call by Lance A. M. Benner, XC426315

Upland sandpiper, Bartramia longicauda, by Johnath, Jun 2010

Call by Andrew Spencer, XC104334

Yellow-bellied sapsucker, Sphyrapicus varius, by Rhododendrites, Feb 2021

Call by G. McGrane, 2006

At the Jurica-Suchy Nature Museum, our nature journaling club, Nature-Doodlers, will be meeting on March 29th, 10am, at the museum to learn about bird observations, drawing and recording our sightings. Make a reservation to come out to this free event by clicking on the QR Code below:

Oak Tree Habitat, pt.1

Oak trees, genus Quercus, have over 400 species worldwide, but almost one-third are threatened with extinction. They are a keystone species, playing a central role in supporting the entire habitat in which they live. They maintain the structure and stability within their ecosystem, substantially affecting the types and abundance of other species. Oaks make up only 2% of plant species, but they directly support more than 30% of all plants and animals.

^{A great oak in Nottingham Forest by Peter Shaw, Getty Images}

Oak trees live from a few decades to several centuries. The Great Oak, Quercus agrifola, a species of Coast Live oak in California, is estimated to be over 2,000 years old. Oaks clean the air by absorbing pollution and sequestering carbon. They provide shelter, food, shade, and help to reduce erosion. Humans get food from the acorns, dyes from the tannin, and wood for construction, ships, and barrels, plus cork for stoppers and oak chips for smoking meat, fish, and cheese.

^{Red oak with new leaves, Quercus rubra, by aleroy4, Getty Images}

^{Oak forest leaf litter in winter by Whiteway, Getty Images Signature}

In spring, tender new leaves containing fresh sap are consumed by a variety of insects. In fall, older leaves will fall to the ground, but are slow to decompose, building up many layers of leaves over time which provide shelter for small woodland ground dwellers and food for decomposers.

^{Branches of red oak with catkins, Quercus rubra,}
^{by anmbph, Getty Images}

^{Texas Red Oak female flowers, Quercus buckleyi by Doug Goldman, USDA-NRCS National Plants Data Team}

Oak trees have both male and female flowers. Male flowers grow in early spring in long clusters hanging from tree limbs. The pollen is a favorite food for a large variety of insects, especially bees. Pollen is released slowly, over several weeks, to be blown by the wind to the female flowers, which appear as tiny, red flowers near the tips of twigs and new shoots. Female flowers are eaten by insects and are a favorite of red and gray squirrels. Oak flowers are one of the earliest food sources for animals in spring, and must be abundant on every tree so that some are able to survive to produce acorns, the seeds of the oak tree.

^{Bur Oak acorns, Quercus macrocarpa; Northern Red Oak acorns, Quercus rubra; Live Oak acorns, Quercus virginiana by Steve Hurst, ARS Systematic Botany and Mycology Laboratory, USDA-NRCS PLANTS Database;}

In late summer, after pollination, the female flower will produce a large, green nut called an acorn, which will mature in autumn, turn brown, and fall from the tree. Acorns are a nutritious food source for many animals, being high in energy, carbohydrates, and fat. In the eastern U.S., many species are dependent on acorn production, and the amount of available acorns significantly influences population sizes. Some acorns will find suitable ground for sending out a root and starting a new tree, but most will be eaten. Masting, an over-abundance of acorns, occurs every few years. It is thought that masting creates a better chance for new oak trees to grow by overwhelming the animal populations’ need for food. As a secondary result, animal populations may expand immediately following a mast year, only to have higher than normal mortality when food resources return to normal for the following years.

^{Bur Oak bark, Quercus macrocarpa by Herman, D.E., ND State Soil Conservation Committee, USDA-NRCS PLANTS Database}

^{Dead oak log in Bialowieza Forest by Nirian, Getty Images Signature}

Oak roots grow close to the ground’s surface and extend well beyond the circumference of the tree’s crown. A complex network of fungi live on the roots and provide additional nutrients to the tree, keeping both species healthy. As the trees grow and age, roots and bark develop crevices and holes in their surfaces, or chunks may become loose, providing niches for plants and animals to shelter and grow. Exposed wood gradually dies and decays providing even more habitat and food for decomposers and the other wildlife that live on them.

In our next post, we will take a look at some of the many species that oak trees directly and indirectly support with shelter, food, and breeding opportunities.

The Woodlands at the Turning, an Illinois oak savannah, by Justin Kern, Nov 4, 2013

Cicadas

Cicadas are found in habitats with deciduous trees on every continent except Antarctica. There are about 3,000 species worldwide; and 170 make their home in North America, including several species divided into three groups with 13-year or 17-year life cycles, found exclusively in the eastern and central United States. The map below shows where various groups are located.

Cicadas hatch from eggs laid in tree branches. After dropping to the ground and burrowing into the soil, they spend the majority of their lives as a nymph living underground. Using their rostrum, a long, sharp rigid structure that can penetrate the outer layer of tree branches and roots, they feed on the sugar and water flowing through the xylem tissue of the tree. Species classified as annual cicadas actually live from one to nine years, some emerging each summer. They are active for four to six weeks to mate, lay eggs, and then they die.

Look closely to see the rostrum sticking out in front of the nose

Magicicada after emerging from final molt by Karly Tuminello

Cicadas have wide set eyes, short antennae, and large, clear wings with membranes clearly visible. The surfaces of their outer wings are covered by small, blunt, waxy spikes. They are water repellant, keeping the insect dry. These spikes can also break up and kill any potentially harmful bacteria landing on the surface.

^{Magicicada species showing short antennae & clear wings by Karly Tuminello}

Beneath the wings are muscular structures called tymbals which can be flexed creating a sound like banging a drum. The buzzing sound commonly associated with cicadas is a result of rapidly flexing these muscles. Tymbals are found on both sexes, and are used to hear sound as well as produce sound. Males often form large groupings to enhance their sound and attract more females to a single location.

Magicicada waiting for wings to harden after molting by Karly Tuminella

Nymphs start to emerge when underground soil temperatures are above 64⁰F, usually in late May in the northern hemisphere. Males emerge about two weeks before females. After emerging, the nymph will find a suitable perch and molt to reveal a fully winged adult; then spend from one to six days waiting for their wings to harden. Males fly up into nearby deciduous trees to find a suitable mating perch and begin calling to attract a female, which will join the male after her molt is complete. After mating, the female lays about 600 eggs. She cuts 25 to 30 small slits in branches and deposits about 20 eggs in each where they will remain for six to ten weeks before hatching. Both sexes may mate several times with different partners, although most only mate once.

Cicada’s mouth parts are strong enough to pierce tree bark, but they do not bite or sting, although they may pierce human skin if handled roughly. They do not pose any danger to humans and have not been known to carry any harmful disease. They feed on sap, not foliage, so they pose no threat to mature trees. Younger or smaller trees with only a few branches may be overwhelmed by the many slits made by a female laying a full brood of eggs. Lots of slits may cause scarring that could kill smaller branches.

^{Empty cicada husks provide food for many species by Karly Tuminello}

Cicadas and their empty husks do provide food for many predators including birds, fish, mammals, herps, and other insects. The emergence of the periodical cicadas will provide a feast for their predators, whose populations will boom next year before being reduced by less available food over the following several years. One theory for why there are periodical species concludes that cicadas emerging in mass numbers can overwhelm the predators need for food, allowing a great number of cicadas to breed and maintain their own high population. Other theories also exist to explain this natural phenomenon, but whatever the reason, they are harmless insects with a very interesting life cycle for us to observe this year.

Tornado

Springtime in the Midwestern United States brings with it everything from light to heavy showers, including tornados. In Illinois, we see an average of 54 tornados a year, with most of them occurring in the month of May. Tornados also occur in other parts of the world during springtime, including Europe, eastern and western China, South Africa, southern Brazil and both the east and west coasts of Australia, but not as frequently as in the U.S.

A majority of storm fronts move from southwest to northeast, which is a contributing factor in the Midwest to the formation of violent storms. There are three types of tornados. Non super-cell tornados are small, narrow, and last for only short periods of time, usually only a few minutes. Wind speeds are low, topping out near 80 mph, capable of causing only minor damage. Squall line tornados are generated by smaller thunderstorms traveling one after another forming periods of rain interspersed with calmer conditions. As the end of a squall line bends, small tornados may form with lower wind speeds, usually causing no damage. Super cell thunderstorms are the largest, most powerful storms that can generate tornados ranging from small to great in size and intensity.

^{Upper left: Thunderstorm during VORTEX2 by Sean Waugh, NOAA-NSSL Lower left: Funnel cloud approaching the ground by National Severe Storms Laboratory, NOAA Right: Supercell often associated with violent weather by National Severe Storms Laboratory, NOAA}

Rainstorms form when cool, dry air overlays a layer of warm, moist air. As the warm air rises to higher altitudes, where there is less air pressure, it expands and cools, losing its ability to hold moisture. As water condenses from the cooling air mass, water vapor floating on the air forms clouds. As more warm, moisture laden air moves into the system, the water vapor droplets become heavy enough to fall as rain. As rain falls, it cools the lower air layer, reducing the warm air flow until the rain stops.

^{Photomontage of the evolution of a tornado : Composite of eight images shot in two sequences as a tornado formed north of Minneola, Kansas on May 24, 2016, by Jason Weingart}

Thunderstorms form in the Midwest from warm, moist air moving in from the Gulf of Mexico and cool, dry air blowing in over the Rocky Mountains. A third source of air from the jet stream may wick away enough rain drops so that the lower air mass does not cool, and the warm air keeps feeding and intensifying a storm. As air moves in different directions and at different speeds, the whole storm will start to swirl, tending to pick up speed toward the center of the storm, eventually creating one or more funnels of rotating air.

Tornados are categorized based on the Enhanced Fujita scale from EF-0 to EF-5. This scale gives an estimate of wind speed and severity of damage inflicted. A little more than half of all tornados are found in the EF-0 range where wind speeds do not exceed 85 mph (137 kph) and damage is minor. Less than 1% of all tornados are recorded in the EF-4 (winds 166-200 mph) and EF-5 (winds over 200 mph) ranges. Another recent discovery is that most of the more severe storms tend to produce multiple tornados rotating around each other. Occurrences of multiple small funnels are difficult to observe within a large and often opaque mass of water, wind, and debris. This discovery helps to explain damages where one house may be completely destroyed while the neighbor is almost untouched.

The afternoon is the most likely time of day for these conditions to exist, once the sun has had a chance to heat the earth and air masses in the lower altitudes. In the Midwest, most tornados occur between noon and 8:00pm. Weather services are constantly monitoring conditions to be able to identify when weather patterns exist that may result in the formation of a tornado. Outside warning sirens are used by many municipalities to let people know that dangerous conditions are imminent. If you are hearing a warning siren, move inside and stay away from windows. Tune into radio, television, or internet resources to obtain the most up-to-date information for your area.

Summer Berries

Across the northern hemisphere, as spring moves into summer, animals are able to find more food sources. Amelanchier and mulberry trees are two fruit-bearing plants that are favorites of many bird and mammal species, including humans.

^{Amelanchier trees by Leonora Enking, Apr 2010}

^{Mulberry flower by Sueviews, May 2006}

^{Amelanchier grandiflora flower by Kurt Stuber, 2004}

Amelanchier is a genus of 30 species of pome-bearing fruit trees in the family Rosacea. This family includes several other fruit-bearing trees including apples, pears, and plums. The tree is a favorite for landscapers with its many white flowers covering the tree in early spring and its brilliant hues of red and orange in the autumn. Amelanchier can be a single stem or a multi-stemmed plant and will grow in almost any soil type, but the ideal habitat is partly sunny, well-drained areas of open woodland.

Amelanchier are known by many names. Serviceberry comes from the fact that when the plants are in bloom, the ground is thawed enough to hold funeral services. In the Cree Indian language, it is known as saskatoon, a name still commonly used in western North America. Shadblow, in old English, refers to a time when the bloom indicated the shad were running. Juneberry refers to the time of year when the berries ripen.

^{Amelanchier fruit by Oregon State University, Jul 2013; Immature mulberry fruit by Geo Lightspeed7, Apr 2022; Unripe white mulberries by Petru Dimitriu}

Serviceberry fruit is slightly larger than a blueberry and tastes of blueberry, lightly peppered with strawberry and almonds. The berries are light green when young and gradually grow plump and sweet as they ripen to dark red and purple. They are a favorite of many bird species including robins and cedar waxwings in my area. Fruit is rapidly eaten as soon as it starts to darken, and almost none is left to fully ripen unless the tree is covered with netting.

^{Cardinal eating mulberry by Carolyn Lehrke, Jun 2015}

^{Robin and mulberries by Zone~V, Jan 2016}

Mulberry trees, of the genus Morus, have 64 species worldwide, and are another important summer food source. Red mulberry, Morus rubra, is the only one native to the United States. White mulberry, Morus alba, is native to South Asia but can be found on many continents, and it is considered an invasive in parts of Brazil and the U.S. All species grow quickly when they are young, reaching heights of nearly 80 feet.

Mulberry trees can be easily grown from either seed or a plant cutting. The market for their fruit is worldwide with some places, such as the U.S., importing millions of pounds each year. While easy to grow, establishing a viable crop for market has many difficulties. Trees do not produce fruit for the first ten years, and their highest yields are when the trees are 30-80 years old. The fruit is a favorite of many bird and mammal species, and is often eaten well before it is ripe enough to pick. Leading producers are Turkey and Iran who have been growing mulberries for several centuries.

^{Pick your own mulberry by Katarina, May 2014}

^{Mulberry cobbler by Eden, Janine and Jim, Jun 2021}

^{Mulberry jam by Amanda Slater, Jul 2021}

Plump, juicy, and sweet berries from both plants are high in vitamin C and iron. Fruits can be eaten straight from the trees or used in a variety of recipes. Other parts of these plants contain a milky sap that is mildly toxic to animals and humans if ingested. The wood is hard, tight-grained and heavy, with many of the same qualities as oak. It is used in furniture and fence posts. Historically, it has been used for arrow shafts and body armor. Amelanchier leaves and bark may be dangerous to cattle, sheep, and goats if consumed in large quantities. The white mulberry, Morus alba, is an important tree for the silk industry. The leaves of this species are the only food source for the silkworm, Bombyx mori; its cocoons are used to produce silk.

^{Silkworm, Bombyx mori, on Morus alba by Gorkaazk}

As you walk woodland areas near your home, watch for berry-loaded trees in your neighborhood. Keep track of each time you see them and what stage the berries are in – and how many are left on the tree. See if you can observe and learn more about who is eating this sweet, juicy food source of summer.

Ferns

Ferns are a group of well-known plants that first developed during the carboniferous period about 350 million years ago when the climate was stable, warm, and wet. Ferns were globally abundant in woodlands and marshlands providing suitable habitat for them.

Ferns were the first group of plants with vascular systems. Vascular plants utilize tube-like structures, called xylem tissue and phloem tissue. Water and minerals are moved from roots to fronds (leaves) through the xylem tissues and are used in photosynthesis to create food that is distributed throughout the rest of the plant in phloem tissues. Vascular systems also provide internal support so these plants can stand upright on their own.

^{Fertile fronds, Christmas fern in Sheipsit State Forest, CT by Holcy, Getty Images}

Early scientists noted that ferns came back every year, but produced no flowers or seeds. In 1669, it was discovered that spores grew on the surface of the fronds, but it was not until the mid-18th century that the entire reproductive process was understood. Spores are one-celled organisms that start to develop in springtime. They appear by the thousands as small green bumps on the undersides of fronds. As summer progresses, the sporangia, a capsule that contains the spore, turns brown. Clumps of these are called sori, and can easily be observed on fern fronds. In late summer, when the sporangia mature, they open and release their spores. Some plants will forcefully shoot their spores away from the fronds and some will open and let the spores drift away, caught by any small breeze.

^{Polystichum richardii in Stanley Park, Akaroa by Jon Sullivan, Aug 2006}

^{Lady fern sporangia by Kerry Woods, Mar 2013}

Most spores will not land in a spot with favorable growing conditions (fertile soil and water), but the spore may remain viable for up to a year, should conditions change. Spores do not contain a small plant like a seed does. A spore starts as a one-celled organism that grows by dividing itself in two during the first phase of reproduction called the gametophyte generation. As this division continues, a small structure called a prothallium grows, getting its nutrients directly from contact with water. Two more structures develop. The archegonium contains an egg, and the antheridium contains sperm. When water is present, the sperm will swim to the egg, fertilize it, and eventually a new, self-supporting plant grows.

^{Crozier shaped fronds by Ray Hems, Getty Images Signature}

The fern develops underground over the winter. In spring, when ground temperatures have risen, fernlets will push tightly coiled fiddleheads through the soil into the open air. A fiddlehead, also called a crozier, is a group of young, coiled fronds (leaves) of a fern. As the fern grows, the upper and lower surfaces of the fronds grow at different rates, and the fiddlehead uncoils, straightening out into several fronds. The plant is entering the second phase of reproduction, known as the sporophyte generation, where spores will be grown on the undersides of the fronds.

^{Green Boston fern frond, Nephrolepsis exaltata by Noppharat05081977 Getty Images}

^{Staghorn fern frond veins by IveehCoombs_Photography, Getty Images}

^{Staghorn ferns by Eyepark, Getty Images}

Ferns can also reproduce through cloning. The walking fern, Asplenium rhizophyllum, grows long fronds that eventually bend over and touch the ground. Wherever a tip touches moist soil, new roots are sent out, and a cloned plant develops. The Boston fern, Nephrolepsis exaltata, grows runners – leafless stems that branch out horizontally. Wherever they come in contact with moist soil, roots are sent out to clone another Boston fern. The staghorn fern, Platycerium sp, grows buds on its roots. As the soil around the plant is moistened by water containing nutrients, a new plant pushes upward through the soil from each bud.

^{Walking fern, Low Tatras mountains, Slovakia by Vrabelpeter1, Getty Images}

Ferns grow well in a variety of habitats. Many species prefer damp woodlands, but some grow on cliff faces or in rocky, dry locations. Be sure to watch for various species of ferns when you are out walking. A good field guide can help with fern identification and provide distinguishing information on this amazing plant group.

Bird Eggs

It is spring in the northern hemisphere, and many birds are claiming territories, finding mates, and establishing nesting sites. Raising new families will take most of the summer and early autumn. As we watch birds who have laid their eggs, it may seem that not much happens until the young hatch, but there is lots of activity taking place.

^{RWBB calling by mirceax from Getty Images}

An ovum, the female reproductive cell, starts its journey to become an egg in the oviduct where it is fertilized by stored sperm from a male and encased in a glob of protein-filled gelatin to form a yolk. Additional proteins, known as the albumin or egg white, are added to nourish the embryo as it grows inside the egg. Calcium carbonate, a mineral added by special cells in the bird’s uterus, encloses the gelatin-like mass of protein and embryo, slowly hardening into the egg’s shell. Egg shells are not completely solid, but are perforated with many minute holes that allow air to reach the developing embryo. Pigmentation is squirted onto the shell adding color and pattern to the outside. A coating of protein determines the outer texture of the egg which may be smooth, glossy, dull, rough, or powdery.

^{Egg collection, Jurica-Suchy Nature Museum, Benedictine University, Lisle by DonArnold}

The total number of eggs laid at one time is called a clutch and some bird species lay only one a year, but many species produce two, or more, annually. A consistent number of eggs is found in each clutch, although additional clutches in the same year may contain fewer eggs. Eggs vary widely in size, shape, and color among various bird species. Egg shapes may be determined by the location of the nest. Cavity nesters tend to have rounded eggs, while cliff dweller’s eggs are often oval with a broad end on one side and a pointed end on the other to prevent the egg from rolling very far. Where a clutch has a greater number of eggs, pointed shapes fit into smaller spaces enabling the mother to easily cover them all when sitting on the nest.

^{Nesting female hummingbird by jaypiercestorffphoto}

Incubation is the process of keeping the eggs warm. An adult usually develops a brood patch underneath its belly where feathers and down disappear and blood vessels close to the skin’s surface can warm the area that is in direct contact with the eggs. Incubation periods are consistent in each species, but may be lengthened by abnormal cold spells.

^{Blue robin eggs in nest by Dennis Flarsen, Pixabay}

^{Western bluebird eggs by Summit to Seashore Birding, Sep 2007}

Color is added into the shell material before it hardens. Colors may vary in hue and saturation on individual eggs, and the deepest hues are often found at the largest end. Pigments are chemicals with complex molecular structures that produce color when mixed with water. Birds have two pigments: reddish-brown hues and bluish-green hues. Here are several theories as to why eggs have markings, but exact reasons are not known.

Heavier pigments are often found in birds that lay their eggs in open, exposed environments, and the markings may serve as camouflage. Many cavity nesters lay white eggs, which are well hidden from other birds, predators, and the sun. Some eggs laid in exposed nests may still be brightly colored, but covered by the female most of the time.

^{Quail eggs showing pigmentation by Piyachok from Getty Images}

Darker colors and markings are often found among species that breed in cooler climates. Pigments are known to absorb UV radiation from the sun and not allow it to harm a developing embryo. But, light absorption by an area of pigmentation generates more heat inside the shell, which may also be harmful. Pesticides and other chemicals in the environment can cause thinning of the shell casing, making them more susceptible to breakage. Pigments tend to gather at weaker spots in the shell casing and have been shown to strengthen the shell.

Several aspects of bird egg development are not yet understood, and many theories are under investigation. An interesting question currently under review is whether a bird, or another animal such as a predator, sees different aspects of the light spectrum than humans. If so, what do birds see when they look at an egg? A new bird’s life starts in an egg, a small and wonder-filled package that has been much studied and yet still presents many unanswered questions.

To learn more, consider visiting your local nature museum.

The Jurica-Suchy Nature Museum at Benedictine University in Lisle, Illinois, has an extensive egg collection displayed by clutch size and covering almost 200 bird species.

Bee An Early Pollinator

There are over 20,000 species of bees world-wide, and more species are found every year. Bees are important pollinators, especially in early springtime. Other pollinator species abound, and all are important to the life-cycle of flowers, but bees are thought to increase seed production by about 70%.

^{Dandelions on day 100 by Mike Deal, Apr 2010}

The bees we see in our gardens are all adults, emerging from their nests between early spring and late summer. The first to emerge are the bumblebees. They have wingbeats of about 200 strokes per minute and a metabolic rate that is double that of a hummingbird, allowing them to generate plenty of body heat to stay warm during cool spring weather. Orchard bees are the next out as soon as daily temperatures stay in the mid-50s. Native honeybees may also come out at about this time, but imported bees cannot fly in temperatures less than 60˚F. Early blooming flowers including dandelion, jewelweed, aster, goldenrod, and clover, are important sources for pollen and nectar in spring.

^{Honeybee covered in zucchini pollen by John Kimbler, Getty Images}

As crop plants start to flower, including fruit trees and vegetables, a large pollinator workforce is needed. Almost one-third of the food consumed by humans comes from plants requiring pollination. As pollen is collected by bees, the grains are spread over the bee’s body, allowing some of those grains to rub off and pollinate subsequent plants as the bee follows a route visiting various flowers. Adult bees feed mostly on nectar, eating very little of the pollen they collect. Pollen is brought to the nest to feed their young.

^{Bumblebee in flight with loaded corbicula by mirceax, Getty Images}

Honeybees and bumblebees have a bare spot on their back leg called a corbicula, surrounded by inward curving hairs. As pollen is collected from each flower, it is scraped into this holding area, which may amount to 20% of their body weight while in flight. After landing, a bee grips a flower tightly with its jaws and legs. Snuggling close to the anthers, the bee vibrates and dances to disrupt the pollen inside and let it fall onto their bodies. They proceed to groom all the pollen grains into the corbicula before moving onto the next blossom. When the corbicula full, the bee will fly straight to the nest, unload all of the pollen, and return immediately to where they left off to collect more.

^{Honeybee collecting pollen into scopa by baianliang, Getty Images Signature}

Other bees store pollen in scopa, tufts of hair on their legs and abdomens. As pollen covers the bee during its flower visits, the four front legs are used to scrape the pollen down past their abdomen where the two back legs pack it into the scopa. Some bees may carry the pollen dry, and others may mix in a little nectar to form a dough-like substance that easily sticks to their body hair.

Brown honeybee heading into narrow opening by Gregory Johnston

Buzz pollination video @ This Vibrating Bumblebee Unlocks a Flower’s Hidden Treasure | Deep Look

Pollen collection has resulted in the development of several adaptations found among many bee species. Electrostatically charged body hair attracts pollen. The charge is a result of air moving across the body while the bee is in flight. When plants are small enough that only the bee’s head fits inside, hooked hairs on faces and under chins allow easy pollen collection. Some plants keep pollen in anthers, long tubes that must be turned upside down and shaken to release the pollen. Many bee species use buzz pollination, hanging onto the anthers to tip them, then vibrating their wing muscles to loosen the pollen, allowing it to fall on themselves.

^{Red head bee, Pachyprosopis eucyrta, licking up nectar by Jean&Fred Hort, Mar 2014}

Nectar provides carbohydrates in the form of sugars and amino acids. Bees use their tongues to lick it or suck it up. Several species have longer tongues for use on deep-necked flowers. Honeybees collect nectar and bring it back to their hives to store it. Over time, some of the water content evaporates, forming honey. This is used as food over winter or at times when other food is scarce. Some bumblebees have been shown to also collect and return nectar to the hive, but don’t create true honey. This nectar is used as nourishment for the hive-bound queen only, not as a food source for the entire colony.

As we begin to see the many blossoms of spring and summer, remember that adult bees are only out in our gardens for a short period of their lives. We can assist their work as pollinators by allowing early spring flowers to finish their blooms before cutting them down.

^{Bumblebee on flower from skitterphoto, Pixabay}

^{Bumblebee collected pollen by vinkirill, Getty Images}

Maple Trees

Maple trees in the northern U.S. are coming into bloom at this time of year. Maples bloom in late winter and early spring, and the flowers come in green, yellow, orange, and red hues. There are about 130 species worldwide, and except for one species, all are found in the northern hemisphere across Asia, Europe, Africa, and North America. Thirteen maple trees are native to North America, and we will take a look at a few of the more common ones.

^{Holland Red Maple Swamp, Wisconsin State Natural Area by Joshua Mayer, May 2012}

Several species are large trees, reaching from 40′ to 65′ in height with 20″ to 60″ diameter trunks. Trunks are dark grayish-brown with ridged bark. Crowns appear generally rounded and root systems are widely spread. Maple trees do well in most habitats, particularly moist to wet soil, along streams or in bottomlands.

^{Sugar maple in spring by J Stephen Conn, Jul 2007}

Sugar maple, Acer saccharum, is well known for its maple syrup, marketed world-wide. When temperatures drop below 40˚, maple trees stop growing and excess starch is stored until temperatures start to rise again. Enzymes in the tree change the starch into sugar which is carried by tree sap flowing through the xylem and phloem cells, located just beneath the bark. A tap gently pounded through the bark intercepts some of the sap and collects it into buckets. It takes 40 gallons of sap to produce one gallon of maple syrup. Historically, the wood was used for railroad rails, plow blades, and wagon wheels. After burning, its ashes are rich in potash and make excellent fertilizer as well as an additive for soap and pottery glazing.

^{Maple tree tapping by PublicDomainPictures , Pixabay}

Black maple, Acer nigrum, is a close relative to the sugar maple, and these two species easily hybridize. Both species are shade tolerant, often found growing together for several years as understory trees. Sap from black maple trees may also be used in maple syrup production. Black and sugar maples are hardwoods, stronger and harder than other maple species, and valued for use as basketball court and bowling alley floors, workbenches, cutting boards, and baseball bats.

^{Bowling alley by vtwinpixel, Getty Images; Maple & other baseball bats by Comstock Images: Maple workbenches from thelinke, Getty Images Signature}

Red maple, Acer rubrum, provides food from seeds, buds, and flowers for squirrels, chipmunks, deer, moose, and elk. In winter, stumps and small twigs are an important food source for rabbits. Pollen is produced early in the spring and is a much needed food source at this time of year for bees and other pollinators. Red maple is also attractive to insects and fungi, which invade the wood and create many open cavities in trunks and large branches, favored as nesting sites for wood ducks and other species.

^{Red maple buds & flowers by Martin LaBar, March 2010}

^{Baby squirrel in maple tree by William Krumpelman, Getty Images}

Red maple has several qualities that have made it a widely used ornamental tree. It grows well in shady sites; it is tolerant of flooding and water-logged soils; it is one of the first to colonize disturbed sites and anchor the soil, and it has a rapid growth rate, colorful flowers and foliage, and lives 75 to 100 years. Maple flavored drinks, such as tea, are made from inner bark scrapings. Bark is also used in the production of ink and black or brown dyes. The wood is used for smoking meat and in the production of some whisky varieties.

Silver maple, Acer saccharinum, is a fast growing tree with a root system attracted to any source of water. It is easily grown in shady areas and wet soils, make it a well-liked ornamental tree. However, it causes many sewer and drain issues in urban settings in its search for water. The wood is hard but very brittle, and branches easily break in heavy winds. This often results in trunks having hollow cavities used for shelter by various animal species including wood ducks and squirrels. Seeds are abundant and are a favorite for birds and small mammals. The sap makes a delicious syrup, but requires twice as much volume as sugar maple trees, making it not commercially viable.

Box elder, Acer negundo, is another maple species that is often found near water. This tree easily tolerates drought and extreme cold, although the wood is weak compared to other maple species, and branches often break when subjected to heavy loads of snow and ice. Box elder produces abundant seeds late in the year that provide a great winter food source for mice, squirrels, and seed-eating birds. Branches are small in diameter, so it is not often used for lumber, but it has several uses as pulp wood for producing crates, boxes, and composite wood panels.

^{Under the spreading maple by Jo Zimny, Oct 2020}

As you are out walking in your area, be sure to look for the many species of maple trees that grow in yards and woodlands, often distinguished by bright flowers, abundant seeds, and lively green foliage. Also, be sure to take the chance to observe their spectacular fall foliage later in the year.

Frog Calling

Spring has arrived bringing rising temperatures, warm winds, and spring rains to the upper Midwest. This is the time of year when many amphibians, most notably salamanders, frogs, and toads, start their annual breeding periods. Illinois has nineteen native frog species. They are secretive and difficult to find most of the year; but spring is the season for mating, and males will leave their woodland homes and make their way to the nearest pond on nights when temperatures stay in the forties or above.

Frogs use a variety of different calls. Advertisement calls, the loudest calls voiced by male frogs, advertises their presence and availability to potential mates. The courtship call, a slight variation of the advertisement call, is used as a female gets close to direct her to the exact location where the male is waiting. If a male mounts an unreceptive female, or mounts another male, which can happen by mistake in the dark, a release call is emitted to inform the male to stop and look for another potential mate. Aggressive calls may be used by one male towards another who gets too close. And if any frogs are attacked by a predator, a loud distress call is made. This may be to startle the attacker or warn other frogs in the area.

^{Waterfall Glen gray tree frogs calling by DonArnold, 2022}

Calls are created by filling the lungs with air, and then blowing out a steady stream of air over the vocal chords. When calling, the mouth and nostrils are normally closed. The air is passed from the lungs, over the vocal chords in the larynx and into the air sac under the mouth. This air sac, shown in many frog pictures, amplifies the sound to help it carry farther. Calling requires considerable energy and may increase the metabolic rate, the rate at which calories are used, from ten to twenty times the resting rate of an individual. For frogs with breeding periods lasting many weeks, the expenditure of calories will cause a male to lose a significant amount of body weight.

^{NoName Marsh, Boreal Chorus & Spring Peeper by DonArnold, Mar 2022}

Many different species of frogs lay their eggs in the same ponds. Males arrive early in the evening and begin advertising, while females arrive a bit later and identify a potential mate based on his call. When a gravid female approaches, the male clasps her from on top and holds on. After a time, the female releases her eggs in the water, and the male immediately fertilizes them by releasing sperm into the water around the egg sac. Depending on the species, all of the eggs may be deposited in one egg sac or in several separate egg sacs. Egg laying can last several minutes to several hours. After each group of eggs is laid, the male and female may separate or rest for a brief period and then move to another spot to deposit more eggs.

Their skin is moist and cool to the touch. It is permeable, allowing air to pass directly through it into their circulatory system, helping to remove some of the workload from the lungs and heart. This can be especially useful during inclement weather. However, the skin’s permeability makes them susceptible to drying out, so they live in or close to water or high humidity environments. Their lifestyle includes being active mostly at night or on overcast days when it is cooler and more humid.

^{From left: Spring peeper calling by Andrew Hoffman, Jan 2000; Ornate chorus frog calling by FWC Fish & Wildlife, Jan 2014; Green tree frog calling by Eyeweed, Dec 2009}

Many frog populations have been impacted by losses of both wetland and forest habitat. Wetlands are used for breeding and forests provide sheltered areas with shade, ground cover, and higher humidity than areas open to bright sunlight. During spring evenings or overcast days, listen closely as you pass by these shady areas and nearby ponds to catch sound or sight of these wonderous small creatures.