Naturalist's Corner - Early Signs of Spring

I am delighted to welcome back guest naturalist Tracey Koenig to our Naturalist column that takes a deeper look at the natural world we see around us as we hike. Tracey, by her own description, is a purveyor of interesting tidbits. She is a retired nature center director currently living in Wisconsin.  Always interested in the natural world, Tracey shares her nature knowledge to help others understand the natural world around them.

I am not a fan of winter. It’s dark and cold when I am craving tropical weather. By the end of March, I am desperate for green and maybe a flower or two. Traditional signs of spring don’t come early enough for me. Over the years I’ve lived in Wisconsin I developed my own signs of spring, even when the snow is still there or after it melts and the brown and gray hues hang on.

Great Horned Owls
One of the earliest signs of spring is the nesting behavior of Great Horned Owls (GHO). In January and February, you can hear the male and female calling to each other, and the female is often sitting on eggs by the end of February. As the male GHO hunts within its territory, the back-and-forth hooting conversation between the owls designates the territory and lets the female know where in its territory the male is. During this time of year keep your eyes open for possible nesting sites and check back often. GHO don’t build their own nests, but they will use anything they find that could contain the family (abandoned hawk nests, squirrel dreys, a crotch of a tree with plenty of leaves and sticks collected there, etc). Keep your distance and protect the location from mass human curiosity. Throughout the time the female GHO is sitting on eggs or very young owlets, the male GHO feeds the female and any owlets in the nest. The female joins in the hunting when the owlets are big enough to be fairly safe alone or when there is no room in the nest for her. It is always amazing to me that the owlets hatch, grow, and leave the nest in about 30 days.

Birdsong
Some birdsong changes as spring approaches. Chickadees are among the earliest birds I listen for. Their “Cheeseburger” call (sometimes described as “Hey Sweetie”) begins in early January and continues into spring. You can’t help but smile when you hear it. Cardinals are also a great early sign of spring. You’ll hear them early in the morning as the sun is rising singing “Cheer, Cheer, Cheer” from the top of the tallest tree in the area. This is a territory call that doubles as a mating call. Once mated, the female adds her voice. This call is repeated well into summer.

Robins
A word about Robins, a traditional sign of spring. I don’t want to burst your joy bubble, but there is a population of robins that stay in Wisconsin and parts of Minnesota all year long. They stick around as long as they have food and water available. This may be a testament to climate change, but maybe even more exciting enough of us have listened to the native plant gurus and have planted trees and shrubs that provide berries for overwintering Turdus migratorius (love the genus name for Wisconsin’s beloved state bird – it means “thrush” and was given to the bird by Carl Linnaeus in 1766). So, look for a large flock of robins when searching for signs of spring. These are the birds that migrate.

Snow fleas

Snow fleas (greatly magnified)
Image -Janice Dinardo

This has been a great winter to see snow fleas (also known as springtails). Don’t worry, they don’t typically show up in your home or on your pet. On warm days in winter, you can find snow fleas if you look closely around the trunks of trees and shelf fungi growing on trunks of dead trees. Snow fleas are tiny (about 1/10”) and dark blue. They look like dirt on the snow until you take a closer look and find dirt in motion. When the temperature falls again the snow fleas return to their winter slumber. As the days stay warmer into March and early April they are active, and an exciting sign of spring. 

Deer fur
Deer have a beautiful, thick winter coat that helps keep them warm. You’ve probably seen deer bedded down in winter covered with snow. That is an indication of just how effective the winter coat is at keeping the deer warm. It’s so efficient that the body heat from the deer doesn’t escape through the fur to warm the air. The darker fur also helps absorb the heat from the sun. Typically starting in March, the deer begin to molt their winter coat to be replaced by a thin, reddish summer coat. This is a messy process that takes time, and it is not unusual to find the deer in what seems like a permanent state of “a bad hair day”.

Blue bunny pee

Blue bunny pee
Image - Andrea Bierbrauer
Heckrodt Wetland Reserve

WHAT? This one is my favorite sign of spring. There must be snow on the ground because you can’t see it on the grass or dirt. There is usually rabbit poo surrounded by blue snow. Late in the winter when grass and other things bunnies like to eat are in short supply, they resort to eating the bark and stems of European Buckthorn. The buckthorn contains a phytochemical that, when exposed to the right amount of sunlight, turns blue. When bunnies are eating buckthorn, their pee also turns blue when exposed to sunlight. Why is this a sign of spring? The sun must be strong enough to initiate the phytochemical reaction, which happens late in the winter, usually in March. 

By late March migratory birds begin to return to the area and I find that I am not so anxious. Moss greens up on fallen logs, making it more cheerful in the woods. Wood frogs will begin to call as the water temperature warms. We notice the growing baby bumps of does (deer) and begin to speculate on single or twin births. Then the neotropical migrant birds begin to arrive and we get swept up in the joy of spring!

Do you have a special sign of spring?