As fall approaches, these very territorial birds become more and more social. Eventually, they come together in groups of several thousand in wetland locations called staging areas. During the day the birds fly away from these areas to feed in preparation for their upcoming migration. They then return to the staging area each night to roost (sleep). Sleeping in large groups give the birds the benefit of greater protection from predators. Soon these cranes will migrate to the southern reaches of the US and northern Mexico.They usually have two chicks who will follow them on their journey. These chicks will stay with their parents until they return to their breeding grounds in the spring and are then chased off. Mated crane pairs stay together year round, and may live to be 25!

Hear this bird’s call: Click

Learn more: International Crane Foundation

 Photos by Laura Erickson

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Sandhill cranes like wet areas and feed on grains and seeds, as well as insects, small snakes, and mice. They weigh about 10-12 pounds and have a wingspan of 6-7 feet! The only other crane species in the US is the endangered whooping crane.

Decidious trees have a chemical clock which tells them when days get shorter and nights longer. This is a sure sign that it’s time to prepare for winter weather and alter their leaves.

How do they do it?

Leaves have several types of pigments (chemicals in charge of color). The one we are most familiar with is chlorophyll, which makes the green color we see in leaves all spring and summer. It’s also responsible for photosynthesis (turning sunlight, water, and carbon dioxide into sugars that feed the tree). In the fall, trees shut down and stops making chlorophyll. As the chlorophyll disappears, another pigment in the leaves become visible: carotenoids. These pigments make the yellows, oranges and browns that we see in sugar maple, aspen, birch, and ash trees.

In late summer, some trees also produce pigments called anthocyanins in their leaves. These combine with the carotenoids and create the bright fiery reds and oranges of red maple, oak, sumac, and dogwood trees.

Why do leaves fall?

As cool weather approaches, a special layer of cells called the abscision layer forms between the leaves and where they attach to the branch. The abscision layer seperates the leaf from the branch and allows it to fall. Oak and beech trees are an exception: their leaves often stay on the tree throughout winter.

Learn more: Why Leaves Change Color

These diurnal (day active) creatures eat seeds, berries, nuts, bulbs, insects, and mushrooms. As winter approaches, they will be caching (storing) these items in special rooms of their private underground burrows. They can store up to 8 pounds of food there! In winter, they will go into periods of deep sleep called torpor, waking periodically to eat some of their cache.

Did you know? Chipmunks have cheek pouches that can stretch to hold 9 large nuts: 4 in each pouch and one between their cheeks. They also use their cheek pouches to carry away dirt from their tunnels which helps them disguise the entrance. Even with this clever trick, most chipmunks only live 2-3 years.

Learn more: Natureworks

 You may have heard the chipmunk’s call: a low “chuk-chuk-chuk.”

Hear this animal’s call

(Photo by John Mosesse/NBII)

As water temperatures in Sunset Lake begin to drop during fall, some drastic changes occur. These changes all have to do with water density. Water has the strange property of being the least dense (lightest) when it is frozen. This is why ice floats in our drinks. Any warmer than 32 degrees and water becomes more dense (heavier) until it hits 39 degrees. At 39 degrees water is as dense as it can be, any warmer or cooler and it becomes less dense. This plays an important role in our lakes and creates a process called turnover.

What is Turnover?

Turnover occurs in lakes in both fall and spring, and is basically the upper and lower layers of water in a lake mixing together. In summer, Sunset Lake is organized by bands of water that are seperated by temperature. This is called thermal stratification. The top band is called the epilimnion and is a warm layer often moved by wind. The water in this band is all the same temperature. The middle band is called the thermocline and holds water whose temperature varies with depth. The thermocline is an invisible wall which keeps the bands of water above and below it from mixing. The bottom band is called the hypolimnion and holds cool, stagnant water which is all the same temperature. Sunset Lake seperates into these bands because its water is different temperatures and therefore different densities.

In fall, the epilimnion (top band) cools and its temperatures become like those of the hypolimnion (bottom band). Once the two bands of water have similar temperatures and densities, the thermocline (middle band) disappears and wind is able to mix all the water together. This mixing is important because it adds oxygen to the deeper water, in which many creatures will need to spend the winter.

In winter, the water seperates into layers again, this time with cooler water in the epilimnion (top layer) and warmer water in the hypolimnion (bottom layer). When the ice melts in spring and warms up to 39 degrees, the water will again be able to mix and spring turnover will occur.

 The dark blue lines in the diagram below represent the thermocline.

Learn more: Water on the Web

October is the month of love for porcupines, a time of year when the solitary creatures briefly pair up. The male sings to the female with grunts, then the two rub noses and touch each others heads with their front paws. In March and April the female porcupine will have a single porcupette. Porcupettes are born with quills, but luckily for their mothers they don’t harden until after they are born. A porcupette will stay with its mother for about 6 months before it heads off on its own.

Through the spring and summer the two will eat leaves, twigs, buds, flowers, and berries. In winter, they will eat the inner layer of bark and needles from coniferous trees. Porcupines also love salt and have been known to chew on things that humans have touched, like canoe paddles and axe handles.

In the winter porcupines sometimes den together in caves, hollow logs, stumps, or trees. Porcupines don’t hibernate, but they also don’t travel very far from food trees during the colder months.

Did you know? A porcupine is covered with about 30,000 quills, but they can’t actually shoot them. The barbed quills get stuck in predators when they get too close and are swatted. A porcupine’s most successful predator is the fisher, but coyotes, red foxes, and bobcats have also been known to catch them. With their excellent defenses, a porcupine’s survival rate is good and they may live up to 10 years!

These nocturnal creatures weigh 15- 20 pounds. That’s one large rodent!

Learn more: Natureworks

This species of sparrow summers and breeds north of us in Canada. Each winter this seasonal guest travels to Wisconsin in search of more plentiful food. The same birds usually return to the same area each year. Juncos eat mainly seed and a few insects during winter, and are often found in large flocks near the feeders at CWES. In order to fuel their little bodies in wintry weather, they must forage at least 6 hours a day!

There is a hierarchy within each junco flock in which the older males are highest, then the females, and then the young birds. This hierarchy determines who gets to eat the best food first. Watch for flock behavior at the feeders: dominant birds will chase lower birds away from food.

Did you know? You can identify female juncos by their more brown color and smaller size. Males usually don’t travel as far south as females. They brave colder weather so that they can get to spring breeding grounds faster.

Learn more: Cornell Lab of Ornithology

​In flight, the junco flashes the bright white feathers on the sides of its tail.

Hear this bird’s call: Click

Galls are odd growths that form on plants in reaction to a parasitic attack. Galls can be found on the leaves, stems, and branches of plants and are often caused by insects such as gall wasps, mites, midges, and flies. Each species causes a specific shaped gall, usually on a specific type of plant.

The gall you are most likely to see at CWES is the oak apple gall, which is caused by a small wasp. These galls form on oak leaves and are best seen in fall when the leaves drop. The oak apple gall wasp has a unique life cycle. In early spring, a small wingless wasp crawls up an oak tree and lays a single egg in a new leaf. When the larva emerges from its egg, it causes a chemical reaction within the leaf which then forms a protective gall around the larva. The larva then eats the growing gall, pupates, becomes a winged wasp, and finally drills a tiny escape hole in the gall in late summer. After emerging and mating, this female wasp drops to the ground and lays eggs in the roots of the oak tree. A year later, a wingless wasp will emerge and start the whole cycle over again.

Another common gall in Wisconsin is caused by a fly that lays her egg in the stem of Canada goldenrod. These bulb-like galls become winter homes for the fly larvae, which then emerge as adults in the summer. Galls usually don’t harm plants, and they actually benefit several animals. Chickadees, squirrels, and downy woodpeckers will feed on the galls, and ice fisherman sometimes use the larvae for bait.

As you’ve watched the many hairy, downy, and pileated woodpeckers at CWES hunt for insect meals this fall, perhaps you’ve wondered how they keep their bird brains safe while hammering away at speeds of 15 mph?

Woodpeckers have several helpful adaptations working for them. First, their sturdy prop-like tail helps stabilize their entire body as they chisel away. Secondly, the woodpecker’s skull is made of thick, spongy bone that encloses their brain so tightly that it doesn’t rattle about while hammering. Lastly, they have thick neck muscles and cartilage at the base of their lower beak that absorb the shock of their blows.

Did You Know? Some woodpeckers have tongues that are longer than their bills and wrap around their skull, beginning at their upper beak, extending around the back of their skull, and ending in their mouths. Many woodpeckers also have tongues with barbed ends for spearing insects, and produce a glue-like saliva to ensure that their meal reaches their mouths. 

 Learn more: PBS

Wisconsin’s smallest owl is a mere 7 inches long and weighs less than a bar of new soap. These nocturnal forest dwellers hunt from perches for their favorite food… mice. A smaller part of their diet is made up of small birds and insects. Saw-whets will lengthen their tiny bodies to look like branches, which helps camouflage them from predators such as larger owls and hawks.

This week, saw-whet owls are making their nocturnal journeys south (some as far as Tennessee) in search of more abundant food. They are one of the few owls to leave Wisconsin for the winter.

Did you know? As with most birds of prey, female owls are larger than the males. This is called reverse sexual dimorphism. One possible reason for this is that larger females produce more body heat for their eggs. Also, the difference in size between the sexes may encourage them to hunt for different sized prey and avoid competing with one another for food.

Learn more: Cornell Lab of Ornithology

Hear this bird’s call: Click

This is the time of year when lady beetles appear to be everywhere, even in our homes! The multi-colored Asian lady beetles seem to especially enjoy creeping into our houses through small cracks and openings. These little creatures are in search of a cozy place in which to overwinter. A good clue for identifying Asian lady beetles is to look for a thick black M or W near their heads.

Asian lady beetles were introduced to the US to control aphids, and were found in WI by 1994. When the little critters get scared or annoyed, they secrete a stinky yellow liquid to ward off predators.

Lady beetles begin life as eggs, emerge as larvae, pupate (somewhat like a butterfly’s chrysalis), and then emerge as adults that can live 2-3 years. Most lady beetles and their larvae feed on tiny insects like aphids who can damage crops.

A lady beetle larva hunting for aphids

 Asian lady beetle, notice the black W near its head.

A native species of lady beetle

With the coming cold, these forest alarm calls are caching large stores of food by burying them near the base of trees. They will return to these caches when winter food is scarce. In the meantime, these chattering creatures defend the territory in which they have hidden their food by chirping, scolding, and chattering at other animals. They can also be seen flicking their tails and jumping from perch to perch when irritated.

Red squirrels especially love pinecone seeds, and large piles of shredded cones are evidence of their favorite eating spots. Such piles of food are called middens. Red squirrels will also eat buds, fruit, nuts, mushrooms, insects, and even bird eggs and nestlings. When spring comes, red squirrels have been known to use their sharp front teeth to pierce little holes in sap-filled trees. They then return to nibble on the sweet leaks.

Did you know? Red squirrels remain active during winter and escape the cold by hiding in dreys and tree cavities. While searching for winter caches, red squirrels are not quite as adept at finding their buried food as grey squirrels.

Learn more: Natureworks

As you’ve walked through the woods at CWES, you’ve most likely come across the sticky seeds of common burdock. The plant is native to Europe and considered an invasive species in America. This member of the aster family was originally introduced to New England by early settlers and has since moved its way across the US. The leaves of this biennial plant are sometimes mistaken for rhubarb. One hint to help tell the difference is feeling the leaves: burdock leaves are hairy. The plant’s leaves also have a bitter taste and are avoided by most animals.

Common burdock has purple flowers that bloom from July until the first frost. From these blooms, a single plant can produce over 10,000 hitchhiking seeds which are dispersed throughout winter. The seed pods are so good at clinging to animals that hummingbirds have been known to get stuck on them. Burdock has been used for a wide range of medicinal uses from treating swollen joints and fevers to coughs and gout. It also has potentially dangerous diuretic effects.

Learn more: Robert W. Freckmann Herbarium

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Cottontails are shedding their summer coat and growing a longer, more grey one for winter. This will help them keep warm and blend in with grey winter trees. If camouflage doesn’t work, the creatures are great at freezing to avoid detection. They can also run at speeds of 13 mph, often in zig-zag patterns, to evade their predators. Look for the Y-shaped patterns their feet make in fall mud and snow.

A rabbit’s teeth are constantly growing. This keeps their incisors nice and sharp for snipping off winter twigs from young trees. A clue that a rabbit has been feeding in an area is cleanly cut branches 3 feet off the ground or lower (deer make higher and messier cuts). Rabbits are crepuscular, which means they are most likely to be feeding and active at dusk and dawn.

Did you know? To digest their food rabbits use a process called caecal fermentation. This basically means that at certain times of the day, rabbits need to eat their feces to get all of the nutrients from them.

​Female cottontails are usually larger than the males.

Learn more: Natureworks

What is Pishing?

Pishing is a sound that birders make to encourage birds to come closer. It sounds a lot like the “sssshhhh” noise that we make when quieting someone, just add a ‘P’ sound to the beginning.

Why Does it Work?

When small birds find a predator nearby, like an owl or hawk, they group together and mob (chase) the predator off. Pishing may sound like the noises these birds make when driving away a threat. The noise then attracts other birds curious about what’s going on. Pishing is best done when you are hidden by trees and can hear or see a bird in the distance and want it to come closer. Pishing doesn’t attract all birds, but chickadees and nuthatches are good responders. The next time you’re on a wooded trail at CWES and hear a chickadee nearby, try this birding trick out!

Learn more: PDF Article by Ryan Zimmerling

In spring and summer these little birds love to munch on small insects, spiders, slugs, and snails. In fall, they store seeds for the long winter ahead in loose bark, piles of needles, and knotholes. Each item is placed in a different spot, and chickadees are able to remember the location of thousands of them! How do they do it? A chickadee’s hippocampus (the area of the brain in charge of spatial memory) actually expands by 30% in the fall. This allows the chickadee to remember its many hiding places. In the spring when a massive memory isn’t needed, the hippocampus shrinks back to its normal size. Wouldn’t it be great if human brains could do that!

Year-long, this little bird is wonderful at saying its own name with a nasal “Chik-a-dee-dee-dee.” Recent research has shown that this call is more complex than we had originally thought. The chickadee’s call is actually an alarm, alerting other birds to the presence of a predator. The more “dees” added to the end of the call, the more dangerous the predator is to the chickadee. Scientists have also found that nuthatches have learned to decode and respond to the alarm calls of chickadees! Even with this great defense mechanism, most chickadees live less than 3 years.

Learn more about the chickadee and hear its call: Cornell Lab of Ornithology

Learn more about the chickadee’s brain and memory: Science Daily Article

Herps is a term used to describe both reptiles and amphibians, creatures which both have amazing cold weather adaptations.

Aquatic frogs: Leopard and pickerel frogs hibernate at the bottom of deep ponds and lakes where there is the most oxygen in the winter. Frogs can breathe through their skin as well as their lungs, and they get their oxygen from the water in this way.

Terrestrial frogs: Wood frogs, spring peepers, and grey treefrogs burrow in leaf litter and wait for something amazing to occur. Special chemical changes take place within their cells, which pack them with glucose (sugar). This allows the frog to freeze solid! While frozen, both the frog’s breathing and heart stop.

Turtles: Snapping and painted turtles make their way to the bottom of deep ponds and lakes and lie dormant there through the winter. Their metabolism slows drastically, so much so that their heart beats only once every 10 minutes! The little oxygen they need is exchanged through membranes in the lining of their mouths.

Toads and Salamanders: These creatures dig into the soil to get below the frost line and spend the winter hibernating there.

Learn more and see some amazing footage of a wood frog thawing: Nova