May is Birthing Season for Birds and Mammals

May 12, 2012

May Daze

How many shades of green exist? Add a ten more and you have May in New Hampshire in the forest. New Hampshire’s natural beauty in May will leave you breathless amid bursting flowers, swarming insects and nesting birds. It is the season when most mammals give birth, the most fertile and vibrant time of year.

It’s said you truly see a place best only when first arriving and upon leaving it for the last time. I was recently reminded of this by a Westerner sharing her first impression of New Hampshire springtime. She remarked about “the welcome close embrace of tall green trees, the smell of abundant moisture, the sheer variety of birds and their calls.” From the perspective of the big sky and arid Rockies of Wyoming, our forested NH hills now seem lush, damp and dripping with birdsong.


The increasing volume of newly-arrived birds is distracting. Northern naturalists experience sensory overload, an “attention deficit disorder” driven by the deafening pulse of life swelling in backyards, farm fields, woods and wetlands. Cool early morning hours are less plagued by intermittent clouds of biting blackflies yet blueberry flowers are often pollinated by blackflies (males don’t bite), so even pests have purpose.

When an approaching warm front is accompanied by southwest prevailing winds, we experience migrant bird “fallout.” I’ve always considered that term too ominous for a phenomenon which brings riotous-orange orioles to the nectar of soft pink apple blossoms. I discovered one new bird species arrival per day in the past week. The mass arrival is annually astonishing.

Surrounding woods now ring with deafening birdsong before dawn. I lose count of the songs of warblers, thrushes, sparrows and flycatchers. I try to recall identities of which species sing various familiar phrases.

The males in bright plumage are wholly consumed with singing. Species-specific songs are repetitive or melodic or whispered lisps or raspy call notes. Breeding birds exhibit an incredible fidelity to very specific habitats. “Witchity-witchity” of common yellowthroat warblers has returned to wetlands. “Pleased to MEET you” of chestnut-sided warblers has returned to thickets of white birch and poplar saplings. In dark hemlock woods, black-throated green warblers sing “zoo-zoo-zeeet.” The gorgeous yellow warblers sing “Sweet-sweet-sweeter than sweet.” They’re right.

While less-colorful, furtive females are occupied with hidden nests where they’ve begun incubating cryptic-colored clutches of eggs. Soon, fledgling chicks will abound. In the local wetland, Canada geese and redwing blackbirds have already fledged chicks. Hen turkeys sit tight on full nests of eggs hidden on the forest floor even as Toms and Jakes continue to call and strut in nearby pastures or clearings.


In mammal world, newborn red and gray fox kits, coyote pups and bobcat kittens are tucked safely away inside hidden dens dug into the earthen banks or beneath fallen logs or in the most inaccessible and steep ledges and talus slopes of the deep woods. Moose cows and deer does are now heavy with unborn calves and fawns respectively. 

Sow bears with single, twin or triplet cubs born in dens last January are now abroad grazing in fields and re-checking sites of last autumn’s birdfeeders. Bears with yearling cubs will soon drive them off in order to mate in June in their every-other-year breeding cycle.

The baby boom of small rodents - mice, chipmunks, squirrels - is now feeding fuzzy owlets also born in March in hollow trees or renovated hawk nests. Soon, thousands of nesting hawks will rebuild coarse stick nests in thick pines or tucked in the crotches of hardwoods. The inexperienced juvenile mice, squirrels and chipmunks will feed hungry hawk nestlings including our most common Broadwing hawks which are now conspicuous in aerial courtship displays and nest building.

The nasal “pee-weet” Broadwing call and drifting petals of apple blossoms punctuates a weekend task: planting corn seed. While doing so, I consider how birthing season is timed to ancient laws of seasonal abundance. When preferred food sources - rodents, insects, apple blossom nectar – reach annual maximum, that’s when survival of newborn young will most successful.

Now imagine if humans themselves shared this ancient common annual birthing season to maximize growth and survival of sun-kissed, chubby, summer infants?

If so, then human breeding season would necessarily occur nine months prior in September. I’m sure some readers may remember a folksy Yankee adage about: “Not when the weather’s hot and sticky…yet when the frost is on the pumpkin…”