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SMRA

The Unseen Jungle

SMRA April 16, 2020

In 1609, Henry Hudson sailed his ship Half Moon from what would soon become New Amsterdam upriver in search of the Northwest Passage, supposed gateway to the riches of Asia. About 30 miles north, after the dramatic palisades along the shore softened into rolling hills, he came upon a stretch where the river broadened to more than three miles from shore to shore. He was certain he’d found his holy grail, which he immediately claimed for Holland.

https://www.nationalgeographic.org/activity/life-on-the-half-moon/

Sorry, Henry. In his defense, Hudson was far from the first to let hopes outpace reality during explorations of the New World. But if he’d had thought to ask the local Native Americans who’d been plying this stretch of water since time immemorial, they would have told him that he’d “discovered” the passage to nowhere but hundreds of miles of more river. 

Hudson was right about one thing, though: This, the widest point of the river’s estuary and now known as Haverstraw Bay, was—and is—something special, worthy of celebration if not of “claiming.” (Note: An estuary is a river’s tidal zone, where freshwater from upstream meets the ocean saltwater. Though estuaries are most often found near a river’s mouth, the tides flow—to a greater or lesser degree—into and out of the Hudson for more than 150 miles, all the way to the Federal Dam in Troy.)

As the Wappinger people, who occupied the east bank in this region, also could have told him, Haverstraw Bay—which stretches from Croton Point north for about six miles—is one of the most important habitats along the whole river. (It’s been designated as a “Significant Coastal Fish and Wildlife Habitat” by New York State.)

The bay plays a crucial role in the river ecosystem, and it all starts with its depth, tidal nature, and proximity to the Atlantic Ocean. It’s rarely more than ten feet deep on its eastern side, and the tides carrying a regular influx of salt water into this shallow, often sunlit expanse help create a fertile brackish environment.

Such conditions, explains Tom Lake, Estuary Naturalist in the DEC [Department of Environmental Conservation] Hudson River Estuary Program, create an ideal nursery for young fish. “Unlike the clear water of the Atlantic,” he says, “Haverstraw Bay is generally turbid, off-color with suspended sediments, making it more difficult for predators to find smaller fish. Inch-long river herring in the open ocean would have a very short expected survival time.”

These conditions also help create a riotous growth of aquatic plants, which provide additional hiding places for young fish. It may be hard to imagine as you walk along the path at Croton Landing or look north from Croton Point Park, but it’s a jungle down there.

Baby Sturgeon. Source: www.riverkeeper.org

And, like all jungles, it plays host to a breathtaking variety and abundance of creatures—in this case, ranging from minuscule plankton to massive Atlantic sturgeon, which can weigh 800 pounds as adults. “Perhaps the key role of Haverstraw Bay,” says Lake, “is that it is a nursery area both for young-of-year fish [fish in the first year of their lives] from further upriver—such as striped bass and river herring—and young-of-year fish from the ocean, including bluefish and Atlantic menhaden.”

The symbol of the Hudson River estuary—the Atlantic sturgeon—provides a vivid example of the interlocking roles of Haverstraw Bay, the river, and the ocean beyond.

Sturgeon spawn in the river north of the bay, mainly from Hyde Park to Catskill. The young fish stay in the river for up to eight years, relying—like so many other species—on the bay for seasonal food and shelter. Then they head out to sea, where they spend most of their long lives (up to 60 years) in the ocean, only occasionally wandering in and out of other rivers from Canada to Georgia.

When males born in the Hudson River are about twelve years of age—and females close to twenty—they return to the Hudson to spawn. This drive to spawn where they themselves were born, shared with salmon and other diadromous fish, shows the ultimate importance of continuing to protect Haverstraw Bay, not only now but for future generations of fish and humans alike.

But the sturgeon and other famous Hudson River denizens—like striped bass, Atlantic shad, and alewives, currently migrating in vast numbers upriver to breed—are far from the only oceangoing fish that depend on Haverstraw Bay. In fact, some visitors over the past quarter century must have deeply startled their first human observers.

“In dry summers, the bay can reach near fifty percent salinity,” Tom Lake points out. “This intrusion of salty water can lure tropical species such as crevalle jack, lookdown, and even bonefish into the bay.” They’re joined by more northerly saltwater fish, including summer flounder, northern sennet (a kind of barracuda), and northern kingfish.

And it’s not just fish that rely on Haverstraw Bay and the entire Hudson River estuary. Far from it. A wide variety of marine mammals have also been recorded there in summer, when, as Lake puts it, “Haverstraw is like an all-night deli.”

Harbor Seal, July 2019, Croton Point, spotted by students from The Rewilding School.
Source: www.rewildingschool.com

In the past quarter century, four seal species (harbor, gray, hooded, and harp), three dolphins (bottlenose and Risso’s dolphin and harbor [common] porpoise), and most famously, even a minke (in 2007) and a humpback whale (in 2016) have paid visits. Perhaps most famously, a wandering Florida manatee made the river its home for a time in 2006.

During my regular walks at Croton Landing, I’ve most often thought of the waters of Haverstraw Bay—slate gray or silvery, calm or roiling—as merely part of the scene’s palette of color and movement. But now I find myself always on the lookout for a passing manatee, leaping sturgeon, or a glimpse of any of the other surprising riches the bay has to offer.

Copyright © 2020 by Joseph Wallace

Pileated-Tongue

Birding

The Tongue Tells the Tale

SMRA April 3, 2020

Today I’m going to spend some time marveling at woodpeckers. In fact, I’m going to marvel at just one part of them: their tongues.

Not that there aren’t plenty of other things worth noticing, starting with the fact that woodpeckers are one of the most diverse groups of birds in Westchester. (And one of the most noticeable and familiar: Every species can become part of our backyard-birding experience, especially during migration season.)

Six species are at least fairly common nesters in this region: the ladder-backed Downy and its bigger cousin, the Hairy; that comparatively recent invader from the south, the Red-Bellied; the quiet and little-seen Yellow-Bellied Sapsucker; the Northern Flicker; and the magnificent, crow-sized Pileated.

That’s a lot of woodpeckers. (By comparison, our region hosts just one chickadee and titmouse and two orioles and tanagers.) But woodpeckers offer more than variety and a percussion soundtrack to a walk in the spring woods. They also serve as spectacular examples of adaptive evolution. There’s so much to say that I’ll focus on three of them: the Flicker, Sapsucker, and Pileated. (I pronounce that “PILL-e-ay-ted,” by the way.)

These three species—like all woodpeckers—eat grubs, ants, and other insects, most often obtained through excavation into tree trunks or limbs. To make this possible, woodpeckers share important features: sharp chisel-like beaks, powerful neck muscles, a thick skull, and a brain designed not to be bruised by repeated impacts.

But the differences in their tongues tell us even more. In each case, the tongue’s length and structure helps reveal where each species hunts, the techniques it uses, and even its preferred prey.

A woodpecker’s tongue

Woodpeckers all tend to have surprisingly long tongues, which are usually stored, remarkably, in a chamber between the back of the bird’s skull and its skin. But Pileateds’ tongues are relatively short, and for a simple reason: The birds’ physical strength and powerful beaks allow them to excavate deeply, reaching their prey without needing an extremely long tongue to do so.

Pileateds’ preferred food includes large grubs and carpenter ants, which can reach nearly half an inch in length. To capture these sizable insects most efficiently, the tip of the Pileated’s tongue is covered with backward-facing barbs. In essence, the bird goes fishing, dipping its tongue into an excavation, hooking its prey, and yanking it out.

Norther Flicker feeding on the ground.

Northern Flickers, on the other hand, rarely excavate in wood at all. They’re much more likely to be seen on the ground, digging into ant colonies. Since the ants they eat are of the smaller varieties, Flickers’ tongues are flattened to provide a greater surface area, but have few barbs.

Like anteaters, which also feast on small ant and termites, Flickers have evolved another useful trait: sticky saliva. The flat, sticky tongue efficiently allows the woodpecker to retrieve a large number of ants at a time.

Yellow-Bellied Sapsuckers have yet another approach to food. In fact, Sapsucker adaptations may be the most fascinating and complex of all.

As their name suggests, Sapsuckers actually do eat sap taken from a variety of trees. (Their favorites range from paper birch to swamp maple to pines and other conifers.) But they do more than just eat the sap: They farm it.

Many of us recognize a row of small, circular holes neatly arrayed in lines on a tree trunk as a sapsucker’s work. One tree may have dozens or even hundreds of holes, located from near ground level high up the trunk.

Yellow-bellied Sapsucker at sap wells.

These holes were not drilled in search of insect prey. They are the “sap wells” of a Yellow-Bellied Sapsucker, drilled specifically to give them access to running sap, which the bird eats. Each sapsucker maintains a territory with its own sap well farm, which it will tend each day and defend against others (including other sapsuckers) that might want to exploit it.

Sap is not the only food this woodpecker relies on. As uneaten sap dries and hardens, it can trap small insects, which become part of the bird’s diet. At certain times of year, especially fall and winter when insects are scarce, the sapsucker will augment its diet with seeds, fruit, and bast (the soft inner wood of a tree trunk or stem). But even here the sap wells play a role: The bast comes from the interiors of the holes they’ve drilled.

Adult sapsuckers feed their young sap and insects as well. Remarkably, researchers have observed parent birds catching a butterfly or other insect, then dipping it in the sap before delivering it to the babies. Presumably, this adds nutritional value to the meal.

What do sapsucker tongues have to do with all this? Plenty. Neither the Pileated’s spear- and fishhook-like tongue nor the Flicker’s flattened, sticky one is designed for transferring a flowing liquid to the bird’s mouth.

But the sapsucker’s tongue is exquisitely well suited to the task. The Yellow-Bellied’s tongue has feather-shaped bristles near the tip, converting it into a kind of sap-collecting brush. Importantly, the tongue’s bristles can hold the liquid more readily through the process known as capillary action. (The same way paint spreads between the bristles of a paintbrush.)

Beyond these three species, each of our other familiar woodpeckers also has its own unique story to tell. Meanwhile worldwide, more than 200 woodpecker species—large and small, spectacular and unobtrusive—occupy tropical jungles and boreal forests, high mountain slopes and sere deserts on every continent save Antarctica.

To see how they do it, just take a look at their tongues.

Copyright © 2020 by Joseph Wallace

web_h_americanrobin_03-16-2016-110-adult-male

Backyard Habitats/ Birding

The World Out the Window

SMRA March 23, 2020

In the world we’re living in for now, it’s a source of solace to me to see how little nature seems to notice or care. The willows have greened, crocuses and daffodils are in bloom, and on a warm day, the turtles in the duck pond down the road from where I live are stacked up on a log…no need for social distancing when there’s a sunny spot to be shared.

Of course, even those of us who are spending much time alone—or in the company only of loved ones—still have the balm that going outside provides. Walks, especially in nature, are encouraged…as long as you keep enough distance between yourself and others. This can provide essential succor for the soul.

But even if you are stuck inside, there’s plenty to be seen out the window, especially in this season. Merely scanning the trees in view can reveal the way the changing season is matched by changing bird behavior.

Blackbird Collage. From Bur Oak Land Trust

For example, sporadically through each day, the trees around my house fill with clamorous blackbirds.

Already I’ve identified four freely intermixing species: European Starlings, Common Grackles, Brown-headed Cowbirds, and Red-winged Blackbirds. (I guess that Rusty Blackbirds could be up there, too, but I haven’t glimpsed one.)  

Sometimes the flocks come swooping down to the nearby bushes and lawns on a multi species raid, but much of the time they’re just perched up there, squawking away. (It’s very strange to hear Red-wings giving their familiar “Conk-a-REE!” call from 75 feet above your head.)

But interesting sightings aren’t limited to the treetops. In the past week or so, robins have invaded the neighborhood’s lawns—and they’re not the patchy, skinny birds we see in windblown flocks in the winter, but brightly plumaged and well-fed as they resume their place as perhaps our best-known nesters. The darker, more vivid males are already keeping a close eye on the females.

Other birds have already paired up for breeding season. In fact, the two House Finches that regularly visit our backyard feeder have been a couple for at least a month. Turns out that these little finches are, in fact, among our earliest songbirds to settle into a season-long relationship. This jumpstart on the breeding process allows them to produce multiple clutches each year.  

Female and male House Finch.
From Celebrate Urban Birds.

Something else I learned about House Finches: The males’ lovely reddish color doesn’t come from a pigment they create, but from the food—berries above all—they eat. Females tend to choose the brightest males, scientists believe, because these males are seen as the hardest workers, the ones most likely to bring home the most food for the brood.

My yard’s Mourning Doves have also become a couple. Though they pick at the safflower seeds in our feeder, they like our back deck even better for sunning, spreading out as flat as they can to soak up the warmth.

Something I’ve noted and wondered about—three Mourning Doves flying in what seems to be tight formation—turns out to be a kind of behavioral display. The lead bird is the male of a mated pair and one of the close followers is a single male ousting the potential invader from its territory.

The third bird? The mated female. Why she joins the chase—instead of teaming up with her mate—appears to be unknown. Maybe she’s just getting a moment’s revenge for all the harassment female birds typically receive in this season.

Carolina Wren. From Celebrate Urban Birds

The third paired-up regular visitors to the feeder, either skulking around under the table on the deck or singing loudly from an exposed perch, are Carolina Wrens. It’s hard to believe it now, when the birds are one of our most noticeable permanent residents (and one of the only species to sing regularly all winter long), but they weren’t always common in our region. In fact, they were most abundant in the South. (Hence the name.)

In recent decades, due to both warming temperatures and the combination of deforestation and reforestation (both of which create the brushy tangles they prefer), the wrens have moved steadily northward in both range and abundance. Today, few suburban streets aren’t given the gift of that ringing “teakettle, teakettle, teakettle, tea!” song.

I love all these species for their very familiarity. But as I write this, just past the first day of spring, the show through the window—and on our streets and in nearby preserves—is about to grow far richer. Warblers, tanagers, orioles, and other gems are already on their way, and I can hardly wait.

by Joseph Wallace Copyright © 2020

Green-Darner-Mark-Chappell

Backyard Habitats

Here Be Dragons

SMRA March 15, 2020

Once, when I was very young—and already fascinated by the natural world around me—I plucked a Japanese beetle off a bush and took a closer look. As it marched across my palm, I inspected its gleaming brown wing cases, their iridescence flashing in the sun.

Then I tossed beetle into the air above my head, watching to see it unfold its wings and fly off. Before it could, though, something shaped like a tiny fighter jet came darting into view. As I watched, the intruder snatched the beetle out of the air and carried it off.

The predator was, of course, a dragonfly. A big green one—a Green Darner, I discovered later. I was immediately fascinated by both its grace and its snatch-and-grab hunting technique, but not until much later did I discover how remarkable dragonflies and their cousins, the damselflies (Order Odonata, called “odonates” as a group), truly are. (You can distinguish the two because dragonflies’ wings are fixed roughly perpendicular to their bodies, while damselflies’ wings fold.)

Images Source: https://www.odonatacentral.org

First I learned how many dragonfly and damselfly species exist. With new ones still being discovered, more than 6000 species have been identified worldwide (they’re native to every continent save Antarctica) and around 200 in New York State alone. The largest known species (Megaloprepus caerulatus, a damselfly whose wings whirl like a helicopter’s rotors when it flies) has a wingspan of about 7.5 inches, while the wingspan of the smallest, the dragonfly Nannophya pygmaea, doesn’t even reach an inch.  

And the common names! Unlike ornithologists, who tend to use plainly descriptive or habitat-oriented names (e.g., Black-Capped, Boreal, and Mountain Chickadees), entomologists have allowed the poetry in their souls to guide them. Thus we have been gifted with the Wandering Glider, Eastern Pondhawk, Halloween Pennant, Ebony Jewelwing, Blue Dasher, and many others.

These glorious names give only a hint of how colorful these insects are. And there’s so much more to marvel at: These small, ferocious predators lead extraordinary lives, the most vivid parts of which remain largely hidden from our view.

For example: Different species employ varying techniques to contend with cold northern winters. Most Green Darners, for example (along some other insects, most famously Monarch Butterflies) migrate to escape the cold weather. Like the vast majority of insects, though, nearly all temperate dragon- and damselflies spend their whole lives in the area where they were born, no matter the temperature.

Remarkably, though, unlike butterflies (which winter over as eggs, chrysalises, or adults in a kind of hibernation), the odonates remain active, feeding and growing all winter long…even during the coldest of cold snaps. The secret of their success is a stage of their life cycle that reads like science fiction.

Dragon- and damselflies are among the most aerial of all insects. They can barely walk (at most an awkward step or two), instead merely perching to rest. They hunt and mate on the wing, and many species even lay their eggs while flying. (If you’ve ever seen a dragonfly seeming to dip its “tail” repeatedly into a pond, that’s a female laying its eggs, often on or among leaves just below the water’s surface.)

Once the eggs hatch out, however, a mirror-image phase of the dragonfly’s life cycle begins: the nymphs not only cannot fly, but live an entirely aquatic existence, walking with ease and breathing through gill-like structures on their bodies. It is this phase that allows our northern species to stay active year-round—because, of course, even under a thick coating of ice, most ponds and lakes never fully freeze.

Nymphs (also called the larvae and, in some species, naiads) are even fiercer predators than the adults, and are especially skilled at ambush hunting. They come equipped with keen eyesight and strong, serrated mandibles, and many species have also evolved a powerful weapon to aid them in the hunt: a long, sharp, prehensile appendage called a labium.

When at rest, the labium folds up under the larva’s head and remains locked in place. But when potential prey—creatures as substantial as tadpoles and small fish for larger dragonfly species—comes within range, the labium unfolds and, driven by hydraulic pressure created by the nymph’s abdominal muscles, jabs forward at great speed.

In some species, the labium impales its prey. In others, pincers at its tip grasp the unwary target. Then the appendage draws back in towards the mandibles, providing the young dragonfly with its next meal.

Nymphs spend months—sometimes even years—underwater before emerging and transforming into winged adults. (Unlike butterflies, dragon- and damselflies skip the pupal stage and emerge fully formed through the nymph’s cracked-open skin. Inspect reeds and other emergent vegetation near waterline, and you may spot the nymph-shaped skins that have been left behind.)

So right now, even though it’s been months since we saw adult dragonflies zooming across the sky or damselflies fluttering amid the flowers, their nymphs are moving amid the fish, tadpoles, and other creatures in our ponds, preparing for the approaching spring…and the next stage in their fascinating and surprising lives.

Copyright © 2020 by Joseph Wallace

Skunk-Cabbage-seashoretoforestfloor-com

Birding

Secrets of an Early Riser

SMRA March 4, 2020

Anyone who’s ever spent time walking through Northeastern wetlands in late winter is familiar with skunk cabbage (Symplocarpus foetidus), one of the earliest flowering plants to appear each year. To this lover of spring, its appearance feels like a joyous harbinger of the glories to come.

Even so, I’ve never paid much attention to the plant itself. It wasn’t until I took a walk recently among the swamps, streams, and wet forests of Pruyn Sanctuary and spotted the purple-and-white foliage emerging through patches of snow and ice that a simple question occurred to me for the first time.

How does the skunk cabbage do it?

Or, more specifically: What enables it to be first, growing so luxuriantly when most plants have barely begun to produce their first buds? The answer—as so often with the natural world when we look at it closely—is fascinating, even astonishing.

Symplocarpus foetidus, it turns out, doesn’t emerge earlier than most other wildflowers because of extra-tough leaves, some kind of antifreeze in its veins, or sheer force of will. It erupts through the snow and ice because, unlike any other plant in our region, it carries its own heating system. It actually functions like (for want of a better term) a warm-blooded plant during those cold late-winter days.

Skunk Cabbage in Snow.
Source: www.twbwf.org

The skunk cabbage generates heat through the process known as thermogenesis, which in fact closely resembles the process used by mammals and other warm-blooded creatures. The process begins with starches the plant has stored in its roots and rhizome (the part of the stem that lies underground), all in preparation for the slightly less cold days of late winter.

Often weeks before most other plants are active, the starches begin to break down, a process that produces a significant amount of energy—i.e., heat. It then exudes the heat through its pores (called stomata) in a process called cellular respiration.

Scientists have found that, over the short term (usually a week or two), a skunk-cabbage plant can warm itself and the earth around it dozens of degrees above the temperature of the surrounding air. In addition, this little engine warms the nearby soil, making it more hospitable to the plant’s growth.

In researching this piece, I discovered that the skunk cabbage wasn’t through surprising me. I’d always assumed that the glossy, mottled purple-and-white shoots that emerge first are leaves. They’re actually leaf-like structures called spathes, which enclose spike-like stems called spadices. (Singular: spadix.) The plant’s abundant clusters of yellowish flowers grow on its spadix, and the leaves—a less glossy green—appear later.

Pruyn Sanctuary boardwalk through Skunk Cabbage leaves in May. Photo: Phil Heidelberger

As so often, the answers to some questions about the world around us only lead to more. For example: Given that the skunk cabbage’s flowers are pollinated by insects, are there enough bugs around in late winter to do the job?

There are, in fact, insects that hatch out at the same time that the cabbage blooms, including its pollinators, flies, stoneflies, and bees. By sending out its flower spike so early, the skunk cabbage is functioning as a classic “early bird.”

The plant’s skunkish odor—most noticeable up close—may also help the plant attract its pollinators, many of which typically feast on carrion and rotting vegetation along with nectar. Even in a season where there may be few insects about, the cabbage makes its presence known to the ones that have hatched.

Even the skunk cabbage’s temporary “warm-bloodedness” plays a part in its ability to thrive under challenging conditions. As well as giving the plant a jumpstart on spring, its self-generated heat may help its insect-attracting odor spread more widely through the air. And once the pollinators approach, the greater warmth within the spathe tempts them inside, where the flowers—and pollen—are.

My walk in Pruyn Sanctuary inspired me to learn about this unique native plant. Even so, for me the best thing about seeing its early leaves—I mean spathes—emerging from the winter earth hasn’t changed at all. To me, the early emergence of skunk cabbage will always mean one thing: Spring is coming. Copyright © 2020 by Joseph Wallace

Pruyn-Sign

Sanctuaries

Pruyn Awakening

SMRA February 23, 2020

Even in the depths of far colder, snowier winters than this one—so far, at least—SMRA’s Pruyn Sanctuary is always full of life. (A feature it shares with all woodlots, marshes, and gardens in the area.)

Reflection on Pruyn ice.
Photo: Joe Wallace

It just doesn’t look that way at a casual glance, because so much of the life is happening out of sight of even the most observant passerby. Beneath the pond and swamp, frogs and turtles are hibernating. Out in the woods, Red-Backed salamanders and Eastern chipmunks are doing the same. Under the ice covering the pond, dragonfly larvae are active, feeding and growing as they prepare for their springtime emergence.

And even though the Monarchs butterflies migrated months ago, other butterfly species are wintering over in the Butterfly and Hummingbird Garden, utilizing a variety of techniques to make it through the winter. (Black and Tiger swallowtails, for example, are currently ensconced in chrysalises, while adult Mourning cloaks are overwintering in knotholes and under loose bark.

But despite the hidden nature of so much of Pruyn’s current activity, a mid-February walk along the sanctuary’s trails and boardwalks reveals abundant signs that the sanctuary is preparing for spring. All it takes is open eyes and ears.

Perhaps the most noticeable evidence is the appearance of the first purple leaves of skunk cabbage coming up through the wet earth—and even through ice and snow—in the sanctuary’s wetter areas. (I’ll write more about this familiar, fascinating native wildflower in my next post.)

Pruyn moss close up.
Photo: Joe Wallace

But it’s not the only plant that marks the change of seasons. Nestled in warm spots and on boulders, mosses are starting to turn freshly green, and vines are sending out new tendrils, and the buds on some larger bushes and trees are beginning to swell.

Insects follow the new growth, and already grubs and other borers are at work…especially in the sanctuary’s invaluable dead trees. (One of the biggest ecological threats to wildlife is the human habit of cutting down dead and dying trees. This “tidying-up” impulse denies insects, nesting birds, and other animals sources of food, nesting spaces, and dens, making refuges like Pruyn even more crucial.)

Pileated Woodpecker excavation. Photo: Joe Wallace

One way to tell that both bugs and birds have been active is to look for trees with large, rectangular excavations in their trunks, often quite near eye level. (And, if the holes are fresh enough, you might spot an impressive pile of wood chips on the ground below.) These gouges are made by the magnificent Pileated woodpecker, a crow-sized, black-and-white bird with a spectacular red crest.

Pileateds, which are year-round residents of Pruyn, excavate for wintering-over insects (especially carpenter ants), though in the coldest months they also include nuts and seeds in their diet. But as soon as the insects become more active with longer days and warming temperatures, so do the woodpeckers.

A couple of recent hours spent walking in Pruyn revealed not only fresh excavations, but a beautiful female Pileated drumming repeatedly (a loud, resonant sound that echoed through the woods) and another—perhaps her mate—letting loose with bugle-like calls.

Other birds, perhaps less spectacular, are also noticing that spring is on the horizon. House finches have paired up—they do this during the winter, giving themselves a jumpstart on nesting season—and the male finches have started singing their cheerful, warbling songs. The White-throated sparrows we’ve been seeing all winter will soon move north to nest—the ones that nest in our region will have migrated from wintering grounds further south— and the males are already getting their singing voices into shape as well.

Common Grackle.
https://www.allaboutbirds.org/guide/Common_Grackle/id

And one of the characteristic sights and sounds of late winter is the appearance of large flocks of blackbirds: Pruyn’s woods are currently full of grackles.

It won’t be long before the sanctuary’s full spring panoply of growth and wildlife activity will be on display. But for now, even the subtle changes on display seem rich, vivid, and full of promise.
Copyright © 2020 by Joseph Wallace

BCCH-Cornell

Birding

The Complicated Chickadee

SMRA February 10, 2020

I admit it: I take Black-capped Chickadees for granted. I mean, I like them: They’re cute, a dependable and confiding visitor to feeders, and one of the few birds that may actually fly over when I show off my “pishing” birdcall to skeptical friends. Even so, to me at least they’ve always been more Old Reliable than Must See.

But it turns out that, as with most things, we miss a lot when we underestimate chickadees. These familiar little birds have much to teach us about taxonomy, speciation, even the evolutionary roots of birds’ learning ability.

David Sibley Art:
Mexican and Chestnut-backed Chickadees.
https://www.sibleyguides.com/?s=chickadee

Currently, seven chickadee species are recognized in North America, ranging from the Mexican, which enters the U.S. almost entirely in the Sky Island mountains of Southeastern Arizona, to the Grey-headed, found only in Northwestern Canada and Alaska. Almost every spot in between has a chickadee species as well…though rarely more than one.

In divvying up the continent in this way, chickadees provide a vivid example of what Charles Darwin first demonstrated with the famous Galapagos finches and mockingbirds: How even subtle differences in geography, altitude, and food sources—like those found between New York with its Black-cappeds and Washington, D.C., where Carolinas are the rule—can cause a common ancestor to split into several different species.

Yet how split these species are remains an intriguingly open question. As a glance at a bird guide shows, the different chickadees all remain so closely related that they resemble those old “find seven differences between the two drawings” puzzles. (The Carolina Chickadee is only slightly smaller than the Black-capped; the Boreal has a brown instead of black cap; the Mountain Chickadee’s “chick-a-dee” call is a little harsher and faster than the Black-capped’s, and so on.)

Two chickadees, with adjacent ranges.
Source: http://www.birdsource.org/Birds/chickadees/

Clearly these little apples haven’t yet fallen far from the family tree. But the real question is: Have they fallen at all? Because, confoundingly, in the small areas where Carolina and the Black-capped Chickadees overlap (a narrow zone running from Kansas east to New Jersey), it turns out that they interbreed freely…and produce plenty of fertile offspring.

Given that our longtime definition of “species” centers on the ability to produce fertile young, does this make Carolina and Black-capped the same species? And if so, how about their cousins, who appear no more distantly related? Could we actually be looking at a single superspecies?  

These are all good questions, though not ones that birders who keep life lists might want to hear. They’re also the same questions that are now being asked about many other bird and animal species long considered separate. (Perhaps most remarkably, polar and grizzly bears turn out to be able to produce fertile offspring, a finding that feels like a harbinger for the future as climate change brings species previously isolated by distance into close proximity.)

But chickadees do more than intrigue genealogists. They’ve also caught the attention of those who study communication—even among different species.

For many small songbirds, “mobbing”—and thus calling attention to—raptors and other potential threats serves as a survival technique. Around here, Black-capped Chickadees often lead the mob, their emphatic “chicka-dee-dee-dee!” calls serving as the first sign that a hawk or owl is in the vicinity.

Their mode of communication is more complex than that, though: The birds actually signal the seriousness of the threat. The greater the danger, the more “dees” the bird appends to the original “chicka.”

When the threat is dire indeed—as with songbird-hunting owls—the chickadee may sound off with more than a twenty loud “dees.” The intensity of the calls can serve as either a warning to hide or a summons to join the mob, dictates that both fellow chickadees and other species (such as nuthatches and Downy Woodpeckers) understand and take heed of.

Chickadees have even more to teach us. How they’ve evolved to ride out northern winters is, in fact, the tale of one of the most remarkable evolutionary adaptations in the animal world.

In spring and summer, chickadees are like many other birds, eating a mix of vegetable matter (mainly seeds) and insects. Unlike most songbirds, though, they don’t migrate to warmer climes in winter. Instead, they remain reliant almost entirely on seeds left over from the growing season, a food source that may be abundant one day, inaccessible or gone the next.

Black-capped Chickadee with seed.
Where might it store it?

To survive these realities, chickadees have evolved the ability to cache seeds, hiding them in many different locations. Sometimes a single bird will cache seeds in more than a thousand different spots.

Caches provide certain food stores, no matter the weather, and using many sites guarantees that another opportunistic seed-eater won’t discover and plunder a chickadee’s entire supply. But this remarkable survival technique provokes a question: How do chickadees find all their hiding places? How do they remember?

The answer is that they rely on their hippocampus, an area of the brain responsible for spatial organization. Simply put, it’s the part that enables them to recognize and identify where they left something.

In many species, including humans, the hippocampus serves this same function. But most of us don’t have to remember a thousand different knotholes or patches of loose bark, much less as a requirement of survival. (Simply recalling where we left the car keys is challenging enough.)

So how do the birds accomplish this herculean task? Through a remarkable evolutionary adaptation: Each year in the fall, as the chickadee gathers its trove, its hippocampus grows as much as 30 percent. It is, in effect, making room for the new memories it will need to endure the winter.

Then in the spring, as abundant new food sources appear and an unerring spatial memory is no longer such a high priority, the chickadee’s hippocampus will shrink down to its previous size. Until the next fall, when the process will repeat.

As I’ve been writing this, a chickadee has been making regular visits to the feeder out my back window. Now, as I watch it fly off in different directions with one safflower seed at a time, I know why. I’m also reminded of something deeper, more essential, about the world around us: Even in small, familiar, and—yes—adorable packages, it remains full of surprise, wonder, and unexpected new knowledge. © 2020 by Joseph Wallace

Australia-Burning-NYTIMES

Advocacy/ Climate Change

Activism in the Age of Climate Grief

SMRA January 29, 2020

The stories are everywhere. Wildfires transforming the landscape of Australia and threatening the Amazon rainforest. Warming ocean waters helping create mega-storms that devastate vulnerable communities. Politicians who not only ignore the clear threats (and the supporting science) but seem to glory in ignoring them.

In the face of such a relentless assault of sad, infuriating, and frightening news, many people turn away Or, at least, choose to learn only the broad outlines of an issue, not the details. For many of us (for I plead guilty to doing this), the only way to stay politically and socially active at all is to fight off the feeling of helplessness—even of despair—that all the details on the news can bring.

But what of the young people who are turning toward these stories, wanting to learn more, not less? Who are majoring in environmental studies, marching in science marches, fighting to change their schools’ environmental policies and investments?

As a writing mentor for many years, I’ve met countless such young people—strong, determined, undeterred. For many of us (again: guilty as charged) they provide our hope for the future, the generation that will finally begin to clean up the ecological messes every previous generation has made.

But that is asking so much, requiring them not only to reckon with an ever-mounting problem but also to overcome the emotional and psychological challenges that accompany the effort. How do they do it? Is it even possible to balance activism and health in the era of climate grief?

I recently talked this over with Delia Walz, a 2018 graduate of Croton-Harmon High School who is now a second-year student and Environmental Studies major at Oberlin College in Ohio. After joining efforts to transform CHHS’s policies on paper use, sale of plastic water bottles, and other issues, she chose to take on the new challenges college’s bigger stage provided.

In making that choice, she came head to head with the emotional cost of doing so. Climate grief is real and ever-present among the students she knows, she says. “It identifies an existential sadness people feel,” she says. “We see students leave the Environmental Studies major because they don’t want to be experiencing these feelings every day.”

On a larger scale, studies show that anxiety about the future is rampant among young people today. A 2017 report by the American Psychological Association said that, alongside the immediate psychological impacts of climate-related disruption due to storms and other threats, “gradual, long-term changes in climate can also surface a number of different emotions, including fear, anger, feelings of powerlessness, or exhaustion.”

Delia has learned that it helps not to take on the burdens alone. At Oberlin, she has become part the school’s branch (called a hub) of the nationwide Sunrise Movement, which advocates and demonstrates for initiatives (including the Green New Deal) to battle climate change and other ecological threats.

A big part of the Oberlin hub’s goal, she said, is to break out of the college “bubble” and work closely with Ohio’s Senator Sherrod Brown, other elected officials, and—crucially—workers who may be suspicious of what such efforts will mean for their jobs. “We have to connect with the unions,” Delia says, “and discuss the safe, well-paying jobs that will be available to them with the development of new technologies through green initiatives.”

In addition, on a college-wide and personal level, Delia says, “We have to work to give support to those who most need it.” One way Oberlin students have done this is to successfully advocate for the establishment of a human-resources position at the school’s Sunshine hub. Its purpose is to help students address their emotional needs.

Other, and timeless, ways of surviving include bonding with other students without talking about the issues at hand. “If you always look directly at the sadness you feel,” she says, “you won’t be able to get out of bed in the morning. But you also can’t succumb to a feeling of guilt if you’re not always looking at it directly.”

Simply taking a break, turning one’s brain off for a little while with TV or another distraction, can make all the difference. “To keep yourself from burning out,” Delia says, “sometimes you just need an hour to be mindless.”

(Among her current escapes—and mine—is “The Good Place,” a TV show with the encouraging belief that people are essentially good, and can change their behavior to improve.)

Yet despite all the challenges they face—both without and within—Delia and so many others remain steadfast in their desire to stay on the path they’ve chosen, to bring about essential change. “I can’t imagine not working together with others towards our common goals,” she says. “They’re too important.”

For the rest of us, those are heartening words, providing strength and determination as we confront our own climate grief.

© 2020 by Joseph Wallace

Turkey Vulture

Birding

Secret Life of Croton’s “Carrion Crows”

SMRA January 8, 2020

You don’t have to be a birder to notice the huge flocks—sometimes numbering 100 or more—of big, dark birds looming over downtown Croton-on-Hudson this fall and winter. Or to know what they are: vultures (often nicknamed “carrion crows” or “buzzards”), those notorious scavengers of road kill and other carcasses that seem to be increasing in number every year around these parts.

Their growing presence is all a glance will tell you about the local vultures, and for many people, that’s all they need to know. But—as with so much in the natural world—if you take a moment to look closer, you’ll see that the story of these big birds is far more complicated, full of surprising twists and turns.

First of all, Croton doesn’t simply have “vultures”: It has two different kinds, Turkey and Black. They’re actually pretty easy to tell apart. The more common TVs, brown-black in plumage, have long wings that slant upwards, forming a V, as they tilt buoyantly in even a slight breeze. BVs, a more recent arrival in our area, are darker (with silver-white patches at their wingtips), slightly smaller and squatter, and have a heavier flight. They flap much more frequently than their cousins.

And while they both have bare, featherless heads, Turkey Vultures’ are pink and Black Vultures’ grey-black. (Bare heads make for less mess when they’re delving deep in a carcass for succulent morsels—and aren’t you glad you know that now?)

But there are other, more fascinating differences between the species. Turns out they also boast dramatically different behavior, feeding habits, and dominance.

For example: Even though we see the two species soaring and roosting together, they don’t actually get along that well. Since Turkey Vultures are larger on average, a single individual can dominate a single Black at a feeding site. But Black Vultures have a way to counteract that size disadvantage: They team up. They form a pack…and a pack of BVs can almost always drive a lesser number of TVs away.

Secondly, while Turkey Vultures depend almost entirely on carcasses for their food (only rarely killing a sick or young animal), Black Vultures hunt live prey much more frequently. The pack mentality, more akin to wolves or lions than other birds, even allows them to bring down mammals such as skunks, calves, and young pigs.

But perhaps the most striking difference between the two species is that they use two entirely different senses to locate carrion.

Black Vultures, like most day-flying predatory birds, rely on their keen eyesight. When foraging or hunting, they soar (and flap) high in the sky, scanning the ground below.

Turkey Vultures, however, use a far rarer—almost unheard-of—method: They employ their sense of smell. Recent research has shown that the vultures possess an olfactory bulb (an area of the brain that processes odors) far larger than that of Black Vultures. In fact, their olfactory bulbs are larger as a proportion of brain volume than those of nearly 150 other bird species studied.

This and other anatomical differences allow Turkey Vultures to recognize ethyl mercaptan, a chemical produced when a dead mammal has begun to decay. The vultures can detect this chemical sooner after death than any other carrion-eater, making them most often the first to the feast.

The same adaptations mean that foraging Turkey Vultures tend to fly low over the canopy, which gives them a better chance of catching that first whiff of ethyl mercaptan. And the Black Vultures? While they soar higher, scanning the ground with their keen eyes, they’re also keeping a close eye on their cousins flying closer to the ground. When a Turkey Vulture locates the carcass first and descends, down swoop the BVs as well. (And then sometimes attack in a pack to drive away the bird that first located the meal.)

Perched on their rooftops and tree limbs, Croton’s carrion crows seem little more than a group of silent, hulking nuisances. But like almost everything in nature, they actually paint an extraordinary portrait of adaptation, competition, and survival. One that rewards a closer look.

Joe Wallace

Frigatebird-allaboutbirds.org

Birding/ Education

Evolution’s Outreach Program

SMRA December 7, 2019

Some years back, I was sitting in my windowless basement writing space in Pleasantville when my phone buzzed. I could see the call was from my wife, and I knew it had to be important: She tried never to disturb me in my writing “dungeon.”

I answered, but before I could say a word she said, “I just saw a frigatebird fly over the elementary school.”

Yes, that counted as important news to this lifelong birder! Also hard to believe. But even as I said, “Are you sure?” I knew how silly the question was. She knows her birds, too, and of all North American species, few are as unmistakable as the Magnificent Frigatebird.

In addition, the appearance in New York of a seabird normally not seen north of Florida was not completely outlandish right then: Just a couple of days earlier, Hurricane Irene had swept through the Northeast, and powerful tropical systems notoriously sweep unexpected birds along with them.

Although I wasn’t lucky enough to glimpse the frigatebird, since then I’ve paid special attention to these one-offs, which happen all the time in our region. (If rarely involving anything so spectacular.) As I write, birders are flocking to a park in Suffolk County to get a look at a Golden-crowned Sparrow, whose normal range isn’t any further east than Nevada. Recently, an Ash-throated Flycatcher (another western species) also visited Long Island.

I’m less interested in checking off these species—the only running bird list I keep is the one for my ABA-area—than in what they tell us about the evolutionary process. Because each time a bird wafts here unexpectedly, what we’re seeing on a micro level is, in fact, an example of one of the engines driving the development of new species. Call it evolution’s outreach program.

Whenever eBird, rare-bird alerts, or other reports list an unusual bird visitor, I’m reminded, of all things, of the Galápagos Islands. Specifically, the birds on this remote archipelago that inspired Charles Darwin to recognize and understand the evolutionary process.

Everyone knows that the Galápagos Islands host birds that—despite originating from a common ancestor—have evolved into different species on various islands and even among habitats on a single island. Most famous of these are the Galapagos finches. (Which, by the way, have recently been moved to the tanager family.)

A diversity of finches!
Source: www.galapagossafaricamp.com

Scientists have not yet agreed on the finches’ likely common ancestor, or even if it came from mainland South America or the Caribbean. One thing they do agree on, however, is how this ancestor reached the Galápagos: accidentally.

Just as the Magnificent Frigatebird was swept to Pleasantville.  (And not just the frigatebird! Check out this post-Hurricane Irene eBird report: ebird.org/news/hurricane_irene_redux/) So were the first finches likely carried by storms. Having arrived in some quantity, they did what living things do when they end up in unfamiliar but friendly territory: They began to breed.

And then evolution did what it does as time passes: The long process of mutation and adaptation began, with the result that the finches not only diverged from their ancestor species, but from each other. All it took was habitat enough, and time.

The same process has been repeated countless times on islands and other isolated areas all over the world (e.g., on opposite banks of the Amazon River, which serves as its own barrier to mixing.) Unexpected arrival, colonization, and speciation represents one crucial way that evolution takes place worldwide.

Admittedly, this is hard for us to comprehend. The problem for us humans, with our brief lives—in geologic terms, at least—is that the development of new species usually takes so long that we rarely get more than a glimpse of it. We have to look at the fossil record—or spectacular examples like the Galápagos—for reminders.

But not me. These days, whenever I see an out-of-place sparrow, flycatcher, or Magnificent Frigatebird, I find myself wondering: “Is this the moment when a new species will begin?”

Joe Wallace

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