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Early spring © Kent McFarland

Field Guide to April 2024

As grays and browns permeate the muddy landscape of late spring, summer colors lie just beneath the surface, almost ready to bloom. Strolling through your neighborhood or favorite woodland in April, you may begin to notice flashy dapples of the season's first wildflowers. The trees around you will start to reverberate with birdsong while the ponds echo with choruses of Wood Frogs and Spring Peepers. If you're lucky, you may even catch the buzz of an early-season bee as it forages. Here’s our guide to some of the new life bursting forth this month.

By Vermont Center for Ecostudies April 10, 2024
Ruby-crowned Kinglet <i>(Regulus calendula)</i> © Kyle Tansley
Ruby-crowned Kinglet (Regulus calendula) © Kyle Tansley

Spring Songsters

By Nathaniel Sharp

Last month, you may have been lucky enough to hear the muffled songs of hesitant Black-capped Chickadees, Northern Cardinals, or Song Sparrows. These half-hearted chirps and warbles can be heard on the rare warm day of March; however, the avian chorus really kicks off in April when the migration floodgates truly open. Red-winged Blackbirds arrive and conk-a-ree from every melting marsh, and winter-resident Northern Cardinals and Song Sparrows seem to have gained new confidence in their singing abilities.

You may soon hear the charming peent of an American Woodcock and, if lucky, witness the amazing spectacle of its dance. Known by names like “Timberdoodle” and “Bogsucker,” this bizarre-looking shorebird spends its early spring days in fields and open lands wet with winter’s melt. Males will choose a displaying territory and participate in elaborate courtship displays involving descents from death-defying heights and musical trilling produced by specialized wing feathers, all in the name of attracting a mate. Join Outdoor Radio and the Mad River Birders on their evening woodcock walk.

Once trees have budded, but before they have fully leafed out, you have your best shot at spotting migratory songbirds like warblers, vireos, and the aptly named Ruby-crowned Kinglet in the treetops. Arriving in mid- to late-April, these birds enjoy a buffet of recently emerged insects before settling down into a territory or continuing on their journey north. Submit your bird sightings to Vermont eBird, and feel free to include photos and comments of your first robin, warbler, or woodcock of spring! This phenological information, just like the blooming times of flowers, can be highly useful in tracking shifts in birds’ migratory timing in response to climate change.

Trout Lily, Dogtooth Violet <i>(Erythronium americanum)</i> © Kent McFarland
Trout Lily, Dogtooth Violet (Erythronium americanum) © Kent McFarland

Spring Ephemerals

By Kent McFarland

Spring ephemeral wildflowers are perennial woodland plants that sprout from the ground in early spring, bloom quickly, and seed before the canopy trees fully leaf out. Once the forest floor is deep in shade, the leaves wither away, leaving just the roots, rhizomes, and bulbs underground. This pattern allows the plants to take advantage of the full sunlight reaching the forest floor during early spring.

Many of these plants rely on myrmecochory—seed dispersal by ants. The seeds of spring ephemerals bear fatty external appendages called elaiosomes. Ants harvest and carry them back to their nests and eat them. The unharmed seeds are thrown into the trash bin and eventually germinate. A single ant colony may collect as many as a thousand seeds over a season. Unlike seeds dispersed by birds or wind, a seed is only carried about two meters on average from the parent plant. With such short-distance dispersal, forest fragmentation threatens the survival of spring ephemerals. Once these plants are gone from the forest, they rarely return.

Long-term flowering records initiated by Henry David Thoreau in 1852 have been used in Massachusetts to monitor phenological changes. Phenology, the study of the timing of natural events such as migration, flowering, leaf out, or breeding, is key to examining and unraveling climate change’s effects on ecosystems. In recent years, record-breaking spring temperatures have resulted in the earliest flowering times in recorded history for dozens of spring-flowering plants in the eastern United States.

You can also add new observations to the record books using iNaturalist! Were he alive today, Henry David Thoreau might be surprised by how many of us are watching and recording flower phenology.

Popular spring wildflowers (click to see field guide at iNaturalist)

Trout Lily (Erythronium americanum)
Bloodroot (Sanguinaria canadensis)
Marsh Marigold (Caltha palustris)
Spring Beauty (Claytonia caroliniana)
Red Trillium (Trillium erectum)
Painted Trillium (Trillium undulatum)
Dutchman’s Breeches (Dicentra cucullaria)
Squirrel Corn (Dicentra canadensis)
Jack-in-the-pulpit (Arisaema triphyllum)

Want to help us make iNaturalist wildflower observations more valuable?

You can help us annotate plant records with their flowering status. Visit a species account, like Bloodroot, for example (below). After you learn more about the plant on the page, click the little gear icon and select ‘Add Annotations for Plant Phenology.’

Scrutinize the image(s) and see if any plants are budding, flowering, or fruiting. If you see any, select one of those for Plant Phenology. If there is more than one stage on a single plant, another Plant Phenology will appear, and you can choose another stage for the same observation. What if it’s bare? If there are no flowers, fruits, or buds, type “Flower Phenology” in the Observations Field and select it from the list. Then add “bare” and click “Add”. See the example below.

Every annotation will help us better understand how climate change is affecting spring ephemerals in Vermont. Happy flower hunting and annotating!

Red-tailed Mining Bee <i>(Andrena erythrogaster)</i> © Spencer Hardy
Red-tailed Mining Bee (Andrena erythrogaster) © Spencer Hardy

April Bees

By Spencer Hardy

Willows (genus Salix) are pollen powerhouses in April. From river banks to roadside ditches, these fast-growing shrubs provide abundant food for early spring pollinators. Their inconspicuous, greenish flowers are visited by a variety of different bees and other insects and are likely the primary pollen source for several specialist bees. These specialist bees are only active for a few weeks in the spring when willows are blooming, from which they frantically gather pollen to provision the next generation that develops over the summer in an underground tunnel. In Vermont, at least eight different species of mining bees (genus Andrena) are considered willow specialists, each with slightly different preferences in nesting substrate, climate, and/or willow species. Like most mining bees, they can be tricky to identify from photographs, though several species in this group are quite distinctive. Learn about each species, then go out and see if you can find any in your neighborhood and add them to the Vermont Wild Bee Survey on iNaturalist!

Spring Peeper <i>(Pseudacris crucifer)</i> © Peter Paplanus
Spring Peeper (Pseudacris crucifer) © Peter Paplanus

From a Peep to a Cacophony

By Kent McFarland

It began as just a few peeps down in the valley, but now a chorus is erupting. In a pond up on the hill, another is just beginning. Within a few minutes, the night is filled with Spring Peepers calling from all directions.


The cacophony emanates from hundreds of males. Each peep occurs when a frog forces air from its lungs, over the vocal cords in its larynx, and into an air sac in its throat. The air enters the sac from openings on each side of the mouth cavity, causing the sac to balloon outward. The inflated sac acts as a sounding board, amplifying the sound and carrying it from the frog to my ears. What sounds like chaos to me sounds organized to a peeper. Several males may interact vocally by forming duets, trios, or quartets, with alternating peep calls and individual notes. When males alternate calls, one individual, the follower, usually calls within 40 to 70 milliseconds from the end of the leader’s call.

Each male peeper can pump out three to four thousand peeps an hour for several hours each night. So it is unsurprising that male trunk muscles, which help propel air from the lungs, average 15 percent of their body mass compared to only three percent for quiet females. The trunk muscle’s aerobic capacity is six times that of leg muscles and, in males, is 17 times greater than that of female trunk muscle. Males weigh, on average, about the same as two dimes, yet their sound pressure is comparable to the song of a warbler (about four quarters in weight) or a blackbird (a whopping eight half-dollars in weight). These little peepers have big bellows!

According to the Vermont Amphibian and Reptile Atlas, peepers can begin calling as early as March 15, with peak activity in early May. But chances are good that the Spring Peeper chorus around you is now happening earlier than in the past, according to findings by biologists James Gibbs, from the State University of New York in Syracuse, and Alvin Breisch, of the New York State Department of Environmental Conservation.

From 1900 to 1912, Albert Wright, an instructor in zoology at Cornell University, visited ponds around campus daily each spring to record the date of the first calling frogs. Ninety years later, volunteers collected the same kind of information for the New York Amphibian and Reptile Atlas, allowing Gibbs and Breisch a chance to compare. Wright, on average, heard his first peepers on April 4. Atlas volunteers heard them around March 20, about 13 days earlier. This April, be sure to record the Spring Peepers near you with the iNaturalist smartphone app and add your observations for science!

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