One of the most abundant birds in North America is making its way back to Wisconsin this month. Male red-winged blackbirds will be returning to wetland areas first to stake out their territories. They will then spend about a quarter of each day defending those territories from avian and non-avian intruders alike. Within a month the more drab brown females will join them. Their nests will soon be woven in the reeds and cattails near Minister and Sunset Lakes, and filled with four bluish-green, brown-streaked eggs.

Did you know? One male red-winged blackbird usually has several mates in his territory. However, males are opportunists that will pursue additional females as well. He isn’t fooling anyone though. While he is otherwise occupied, it’s not uncommon for his mates to breed with intruding males. In fact, 25-50% of the young in a male’s territory may not have been sired by him!

Learn more: Cornell Lab of Ornithology

Hear this bird’s song

The gray squirrel’s smaller, more aggressive cousin has spent the winter tunneling under the snow in search of stored food. During this season, male red squirrels are actively fighting over territories and their warning, “cherrrr” call is once again heard in the woods. After a pair of red squirrels mate, the female will make a nest in the cavity of a tree or construct one out of leaves and sticks on a high branch. In about a month, 2-5 young will be born, and by May we might catch them out and about exploring the woods. Sometimes, a second litter of young are born later in the summer.

Red squirrels especially love pinecone seeds, and large piles of shredded cones are evidence of their favorite feeding spots. Such piles of food are called middens. Red squirrels will also eat buds, fruit, nuts, mushrooms, insects, and even bird eggs and nestlings.

Did you know? Only about 25% of baby squirrels survive to adulthood. Their longest lifespan is 7 years in the wild.

Learn more: Animal Diversity Web

As spring birds begin to return, here is an interesting technique that you can try to get a closer look at them. Just make sure to use this trick sparingly.

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: http://www.bsc-eoc.org/download/BWCfa05.pdf

Spring is on its way, but there is still not much green to be seen. There are, however, two evergreen species of fern at CWES that have remained green year-round: the intermediate wood fern and the polypody fern. Intermediate wood ferns can be found near many of the forested trails at CWES, and the polypody fern can be seen clinging to the hillsides (especially near the firebowl). Flip over the fronds of both of these species and look for the tiny reproductive spores underneath.

Fern Lingo

The leaf of a fern, from tip to root, is called a frond. The small leaflets that make up the fern frond are called pinnae. Ferns reproduce using tiny clumps of spores called sori. A fern will drop millions of sori in its lifetime, but only a few will land in a spot with just the right light and moisture to grow.

(You are looking at the pinnae of a fern frond. The brown dots are the sori)

Did you know? Ferns have been around since before the time of dinosaurs!

Learn more: Ferns of Canberra

Every year about this time, you can find the familiar American robin returning from their wintering grounds in the southern United States and Central America. Males return about one week earlier than the females, and often come back to the same nesting area year after year. Robins will re-use their old nests, which can be found in trees or on buildings. A robin’s nest is usually made of mud and plant material. The female is in charge of creating the nest, and will usually have two clutches of three or four eggs in it each year. She sits on the eggs for about two weeks, while the male defends the area. Of course the male will sit on the eggs every once and a while to give the female a break.

Once hatched, the young stay in the nest for about fifteen days, then it’s time for the second clutch. The main diet of the robin is berries, along with insects, larvae, and worms.A robin’s diet changes throughout the day. In the mornings they focus more on worms, but change over to berries later in the day.

Did you know? Even though a robin looks like he’s “listening” for a worm when he cocks his head sideways, he’s actually looking for tiny movements that would indicate a worm near the surface.  Also, did you know that the American Robin (Turdus migraatorius) is in the thrush family, which also includes bluebirds?

If a robin is very lucky it may live to be 14 years old. Because of how often this bird hunts on lawns, it is susceptible to chemical poisoning.

Learn more: Cornell Lab of Ornithology

Track this bird’s northward migrations: Journey North

Hear this bird’s song of “cheerily, cheer up, cheer up, cheerily, cheer up.”

These slimy creatures have spent the winter deep underground, hiding from frigid air temperatures. With warming days, they become more active and crawl towards the surface in search of better food: decaying plants and animal material. Earthworms are not native to Wisconsin and were not naturally present here after the last ice age. They likely came here as eggs brought in with soil by the early Europeans.

While these wriggling organisms are wonderful in gardens, they are having a negative impact on the northern hardwood forests across this region. When earthworms are in an area, they digest nutrients and leaf litter much more quickly than native bacteria and fungi. This means that soils become compacted and there are fewer nutrients available to growing plants. Consequently, some populations of plants are having a difficult time surviving. Take care not to introduce an exotic worm to an area by disposing of fishing bait in the trash and not moving soil from one ecosystem to another.

Did you know? If you cut a worm in half, there is a slight chance that one half will survive. Some species of worms can regenerate (regrow) their tails. So, if a tail segment is removed, the head half may survive. Earthworms have light sensitive cells near their “heads,” but have no eyes. Earthworms are also hermaphrodites, meaning they have both male and female organs.

Learn more: Wisconsin Natural Resources Magazine (Worm Invasion Article)

The Adventures of Herman (Anything you might ever want to know about worms)

Above freezing days and freezing nights are conditions that cause trees to begin pumping their sap upward, usually during the daytime. Sucrose stored in tree roots and made by last year’s leaves is sent high into developing buds. This allows new leaves to unfurl. Sap will continue to flow steadily upward for about a month.

Humans aren’t the only ones to take advantage of the sweet sap, creatures like red squirrels have been known to pierce branches and then return for the sweet sap congealed there. As you might expect, sugar maples are the trees with the highest sugar content in their sap.

Did you know? It takes 30-40 gallons of raw sap to create one gallon of the syrup we use for our tables.

Learn more: Cornell Sugar Maple Research and Extension Program

This butterfly is one of the few to overwinter as an adult in this area, and has spent the cold winter months under the bark of trees. During the first warm days of spring you may glimpse one fluttering around CWES. Because it emerges so early in the year when no flowers are available, it relies on tree sap for food.

When this insect’s wings are closed, they are a mottled brown and blend in very well with tree bark. When opened, bright orange and blue wing borders are revealed. The mourning cloaks that we see in early spring have dull and battered wings from their previous months of life. The individuals that we find later in the summer will have just emerged from chrysalises and be much more colorful.

Did you know? This butterfly is one of the longest-lived in Wisconsin with a lifespan of 10 months!

Learn more: Wisconsin Butterflies

This month, sandhill cranes are returning from wintering areas as far south as Texas, Florida, and Mexico. They will soon be searching for food such as grains, seeds, invertebrates, and small animals, as well as a place to mate and raise their young.

We will soon hear pairs of these birds unison calling as they court and re-establish their bonds in areas near Minister Lake. Pairs will also perform complex dances as part of their courtship displays. Nests will then be built in wetlands from plant materials, and eggs will be laid sometime between now and late May. Both parents incubate their two brown eggs for about a month. Pairs stay together year-round and migrate with their offspring who they will care for until they are 9-10 months old. The young then won’t breed until they are 2-7 years of age.

Did you know? In spring these large birds, with a 6.5 foot wingspan, actually preen mud into their feathers to help them blend in with nearby grasses.

Learn more: Cornell Lab of Ornithology

Very soon, the only marsupial in North America will give birth to about 7 naked, bean-sized babies. These little ones will immediately crawl into their mother’s pouch, where they will grow and stay protected for the next 2-3 months. When they are large enough to leave the safety of the pouch, they will hitch a ride on their mother’s back.

The Virginia opossum is a nocturnal creature that eats a wide variety of food: insects, fruit, snakes, small animals, and eggs. In turn, opossums are also eaten by many predators such as owls, coyotes, and foxes, and are lucky if they live 3 years.

Did you know?  It’s true that when threatened the opossum will “play” dead. It will even roll-over, stiffen, drool, and slow its breathing. This coma-like state can last up to four hours, enough time to fool some predators. The opossum got its name from Captain John Smith in 1608. He got the word from the Algonquin name “apasum”, which means white animal.

Learn more: Animal Diversity Web

From now until May, this large bird will be picking out a mate and building a stick nest in a tree near water. A nest is usually built in the same area as hundreds of other heron nests, in a place called a heron rookery. Both parents then incubate their 2-6 light blue eggs there. If the chicks make it to their first birthday, they may survive to 15 years of age!

To catch meals of fish, amphibians, birds, and aquatic insects, the 4-foot tall heron wades into the water and waits for prey. It then spears and swallows its food whole. Great blue herons have even been known to choke on prey that is too big!

Did you know? The great blue heron is the largest heron species in Wisconsin. You can tell this bird from the similarly-sized sandhill crane in flight because the great blue heron bends its neck (see below). 

Learn more: Cornell Lab of Ornithology

Kingfishers are appearing along the lakes and rivers of Wisconsin this week. The kingfisher is one of the few bird species in which the female is more colorful than the male. Female kingfishers have a rust-colored chest band and sides that are white on the male.

Kingfishers eat mostly fish, but will also hunt reptiles, amphibians, and crustaceans. Any food material that can’t be digested gets regurgitated later in the form of a pellet.

Did you know? Kingfisher pairs create unique nests in the spring. They dig tunnels into the banks of streams and lakes that range from 1 to 8 feet long! The kingfisher has two specially fused toes that act like a small shovel to help it dig its nest. For a picture of a kingfisher nest from the EPA’s website click here.

Learn more: Cornell Lab of Ornithology

Listen to this bird’s rattling call

On warm days, you may glimpse jumping spiders emerging from a long winter’s nap. These tiny, dark spiders populate the tall grasses near Minister Lake where they wait for insect meals. A jumping spider’s eight eyes have some of the best vision in the spider world. Once they spot their prey, these arachnids use their powerful back legs to leap at it, up to 40 times their body length! Although they do not spin webs jumping spiders, like all spiders, can make silk. They use theirs as a type of safety cord to hold them when they leap into the air after prey.

Did you know? There are at least 500 species of spiders in Wisconsin. In the spider world, male spiders are usually smaller than females!

Learn more: Spider Web Watch

Learn about spider anatomy: University of Kentucky Entomology

While this yellow weed is very familiar to us here in Wisconsin, it originally came from Europe. Its name comes from the French dent de lion, which means teeth of the lion and refers to the plant’s leaves. If you take a close look at a dandelion flower, you’ll find that it is actually made up of many tiny flowers called florets.

This perennial plant (comes up every year) has many uses: leaves are nutrient-rich and can be eaten in salads; flowers are used to make wine; and roots can be roasted to make a coffee substitute.

Did you know? Part of the dandelion’s success story has to do with its deep taproots, which can reach as far as 5 feet into the earth. If you try to pull out the plant and leave behind even a bit of the taproot, the plant will simply re-grow from it.

Learn more: Robert W. Freckmann Herbarium

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