Listen to the Spring Songs

April is the month—at least in the Northwoods—when spring really comes alive. The ice may not all be melted, but open water is plentiful along the edges, shallows, and streams. Snow lingers in north-facing hollows, but mud glitters in the sunny spots. Best of all are the sounds of our friends returning from their winter travels. I like to loosen up my legs and work fresh oil into my chain with a leisurely bike ride along Lake Namakagon.

American robins only migrate as far south as necessary to find wrinkled apples for breakfast and weather that is a little less harsh. They are some of the first to return and begin shouting for joy with notes that alternately rise and fall. Here I am! Over here! Cheer up, cheerio, cheerily! It’s worthwhile to listen intently to the tone and quality of their syllables, because once more birds start to arrive, there are a few species whose songs resemble the robin’s—with a twist.

Rose-breasted grosbeaks—those delightful gents with snappy black backs, white chests, and bright red cravats—sing a sweeter melody with fewer pauses. The red-eyed vireo is less hurried, pauses between each phrase, and is in it for endurance. One olive-green male was recorded singing 20,000 songs in a single day! The aptly named scarlet tanager is my favorite. Their raspy phrases are usually described as a “robin with a sore throat,” but to my ear, their whiskey voice is the sexiest of all the birds.

Beaked hazelnut bushes catch my eye with their delicate twigs and little brown catkins as I push my bike through a pile of slush. Erupting from the tip of one brown bud is a fountain of tiny scarlet tentacles. Sticky stigmas at their tips reach out to grab pollen from another hazel’s catkins as it floats through the air. Pollen tubes grow down through the skinny style to the flower’s ovary and fertilize the ovules. By fall, the ovules will have grown into tasty hazelnuts to feed many wildlife species. For now, this first flower of spring feeds my soul.

Damp soil is inconspicuous until a warm breeze lifts its molecules to my nose. Microbes in the soil have revved up in response to spring’s warmth. Their waste, reproductive spores, and even their dead bodies contribute to a scent called “geosmin,” which also gives wine its terroir. Digging around in the same soil releases the common microbe Mycobacterium vaccae into the air we breathe. Inhaling it has been shown to increase serotonin levels in mice and help them navigate a maze. The effects do not last long, and scientists surmise that humans would need to be exposed about once a week to become happier and smarter. I inhale deeply.

Wood frogs spent the winter hunkered down in the dry leaves on the forest floor, underneath the snow, frozen almost solid. When rain and sun finally find these northern-most occurring amphibians, they defrost from the inside out. The wood frog’s heart starts beating before it is fully thawed. Breathing resumes soon after, and circulation begins as soon as their blood begins to flow. A few days later, they are ready to mate. Males head to the nearest woodland pond and then make quacking calls to attract females. The calling pauses briefly as I bike past—being noisy makes them vulnerable to predators—but soon the urgency of their quest overcomes fear. Their tadpoles must be ready to hop away before the pond dries up!

Dark-eyed juncos hop, sparrow-like, on flattened brown pine needles looking for seeds. The first winter flurries brought these slate-gray birds south from their nests in Canada. Now they seem to follow the receding snowline back north. This pattern has earned them the nickname «snowbirds.” Bright white feathers on the outer edges of their tails flash as the flock startles ahead of my approach.

Speckled alder bushes scraggle up from a ditch that doubles as a wetland. The speckles on their bark are actually small slits called lenticels, which allow the plant to breathe even when its roots are drowning. Like hazels, their flowers are borne in cylindrical clusters called catkins. I can’t resist giving the catkin a quick flick, which sets a cloud of yellow pollen drifting. Humming, a black-and-yellow bumblebee with an orange belt, visits the catkins, too.

Ruffed grouse are difficult to spot, but the sound of their drumming permeates the spring woods as the males try to attract females and warn the other guys away. The noise doesn’t come from them hitting the log, or even their own, mottled-brown chest. The downstroke of their wings forces air out, while the rapid upstroke creates a momentary vacuum. Air rushing in to fill the vacuum makes a mini sonic boom. The thumps start slowly and accelerate rapidly, sometimes tricking me into thinking that my own heart is racing out of control.

Common loon wings are built for diving underwater, and the same stiff feathers that compress air out of their body also make a sound like a locomotive when beating the air. A wavering tremolo flight call adds to the urgent feel as this loon looks for a place to land. Not just any open bay will do. Loons have the heaviest body paired with the smallest wings of any bird that can still fly. Like a jet airplane, they need a long runway to become airborne. But their feet are placed like an outboard motor at the back of their bodies, which makes walking almost impossible. In their case, the runway must be open water. They must choose their landing carefully.

Cold wind buffets me from across the mostly frozen lake. A warm breeze exhales from the snowless, sunny woods. April is the windiest month. Tonight, stark temperature differences will send gusts howling through the trees and cram punky chunks of ice against the windward shore. Tomorrow, when the loon returns, open water will be waiting.

Every day brings new delights as the robins’ incessant songs wake up spring in the Northwoods. “Cheer up!” they shout, and it’s almost impossible not to heed their advice.