Spring Bird Migration and Nesting Wonders to Watch in April

Field report

The return of migratory songbirds, a spectacular wave of nesting activity, and wildflowers carpeting the forest floor all feature this month.

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Whereas March gently ushers in the spring season, it's April that enthusiastically flings open the doors to warmer days and balmy nights. The transformation is most noticeable during the evening hours, when the hushed silence of winter gives way to a lively symphony of spring peepers and birdcalls, celebrating a world awakening from its frosty slumber. Amidst this jubilant nocturnal resurgence, the relatively early darkness of the evening still offers a perfect opportunity to witness nature's nighttime performers! Here are some ecological highlights that await curious observers. Wishing you vivid discoveries!

Grab Your Binoculars: It's Peak Bird Migration Season (all month)

Chris Mihos (Case Western Reserve University)/ESO

As the northern hemisphere welcomes the onset of spring, it simultaneously heralds the arrival of one of nature's greatest spectacles: bird migration. What makes this season so special? During winter, forests fall quiet as songbirds depart for warmer latitudes. But in spring, the flyways come alive again as millions of warblers, thrushes, tanagers, and flycatchers journey northward to claim breeding territories.

Until the close of May, woodlands and wetlands brim with arriving species, captivating the hearts of birdwatchers everywhere. Eager to embark on a birding adventure? Your local Audubon chapter provides valuable guidance onhow to spot dozens of species during this period. To get the best views, it is suggested that you head out at dawn with a pair of binoculars and a field guide.

Marvel at the Burst of Spring Wildflowers (April 6)

April's peak wildflower display, nicknamed after the rush of color from springtime blooms of creeping phlox (Phlox subulata), reaches its most vibrant in the early morning hours of April 6 when forest floors are carpeted in white and pink.

According to naturalists, some additional seasonal markers for April include "Breaking Ice Moon" (Algonquin), referring to the thawing of frozen ponds, and the "Moon When the Ducks Come Back" (Dakota), marking the return of waterfowl to northern wetlands. Down in the southern hemisphere, where the transition to winter is underway, the Māori of New Zealand refer to April's Moon asHaratua, which means "Crops are now stored in pits. The tasks of man are finished."

Frogs and Salamanders Reach Their Breeding Peak (April 11)

On April 11th, amphibian activity reaches its peak in vernal pools across the temperate world, presenting the most favorable evening of the year to observe breeding frogs and salamanders. During this period, spring peepers and wood frogs will be calling at their loudest, and spotted salamanders will be making their nocturnal migrations to breeding ponds. If you're in a spot near a wetland, the deafening chorus of frogs is impossible to miss.

Amphibian activity will be at its peak for the year in the days leading up to and following April 11th. As the month of April comes to an end, frog choruses will gradually quiet, with many species having laid their eggs and returned to the forest floor. This brief window offers a unique opportunity for nature lovers to witness the extraordinary spectacle of hundreds of frogs and salamanders gathering in the same small pond.

A Quiet Forest Walk Reveals Nesting Secrets (April 20)

NASA/ESA and The Hubble Heritage Team (STScI/AURA)

Just like last month, we're headed into the later part of April with a window of settled weather and quiet trails. For a few days leading up to and after April 20, you can walk forest paths with minimal disturbance and be treated to intimate views of songbirds building nests, early wildflowers pushing through leaf litter, and other signs of renewal that fade as summer greenery takes over.

Need a destination? This month, we're recommending a visit to your nearest mature forest with a closed canopy and rich understory. Located in patches across the landscape, these woodland gems are "biodiversity hotspots" due to their exceptionally high concentration of nesting birds, emerging insects, and spring ephemerals. They are overall roughly five times as species-rich as younger woodlands (with their shrub layer nearly 100 times denser) andcan be found in nearly every county.

A Rare Synchronized Emergence of Cicadas Unfolds Underground (April 20)

On April 20, a rare event called a periodical cicada emergence will occur for select areas in the eastern United States. This phenomenon takes place when millions of cicada nymphs tunnel out of the soil after spending 13 or 17 years underground, climbing onto tree trunks to shed their exoskeletons and take flight for the first time.

A periodical cicada emergence is distinctive because of its sheer scale and synchrony. In this case, the densest populations emerge in a specific region, while surrounding areas witness only scattered individuals. These mass emergences are quite rare, occurring only a few times per century in any given location. When they happen, the noise is overwhelming—males singing in unison can reach over 90 decibels, louder than a lawn mower.

For the upcoming emergence, the regions that will experience the greatest numbers include parts of Virginia, West Virginia, and North Carolina. To learn more,check with your local extension office.

Catch the Dawn Chorus and Put It in Your Memory (April 22/23)

The spring dawn chorus will reach its peak intensity on the mornings of April 22/23, with calm weather keeping conditions perfect for even the softest birdsong to carry.

Dawn choruses aren't known for being a single-species event—dozens of bird species sing simultaneously, averaging around 20 distinct voices at peak moment. That said,field guides reportthat about a quarter of songs come from just a few dominant species—a nice bonus for those still learning to identify bird calls by ear. If you're willing to wait until next year, you can witness an even more intense chorus as late-arriving species join the mix. This layered symphony builds every spring as each species returns on schedule from its wintering grounds. In some years, the chorus is so dense it feels like the trees themselves are vibrating with sound.

To experience it, find a nice patch of woodland or meadow free of traffic noise. The songs will appear to come from every direction (which is easy to appreciate thanks to the inclusion of robins and cardinals, among the loudest and most recognizable singers).