Wood Thrush: The Pavarotti of our Forests

When I got out of my car at the Center last Thursday morning, I was immediately greeted by one of the happiest sounds of the forest: the melodic church-organ voice of the wood thrush. A very close cousin of the uber-common robin, the wood thrush is one of the most important birds you should introduce yourself to as quickly as possible.

And a simple walk on our trails or along the Wissahickon should help you accomplish that.

A migrant, the wood thrush has only recently returned from its winter haunts in Central and South America. So its call is one of the keystones in my springtime arch– as is the first skunk cabbage, the first butterfly, the first warbler, the first turtle along our pond’s ledge. While last week’s call was not the first of the year– that came in April– it was a happy reminder that some parts of the world still work.  

The call is throaty and lush, a “haunting ee-oh-lay,” says on one website, with a bit of vibrato. It’s widely considered the preeminent songster of a Pennsylvania forest, our Adele, our Pavarotti. No less an observer than transcendentalist Henry David Thoreau agreed. “The thrush alone declares the immortal wealth and vigor that is in the forest,” he wrote. “Whenever a man hears it, he is young, and Nature is in her spring. It is a new world and a free country, and the gates of heaven are not shut against him.”

Doesn’t that alone make you want to go hear one? “Ethereal” is one descriptor you’ll encounter when reading about thrush song, as it uncannily can whistle two notes simultaneously, harmonizing with itself to produce the ringing that is so entrancing. It sings at both sunrise and sunset, making it one of the very first– and very last– birds you will hear that day.

It’s male that sings, often on an exposed perch in a tree, and the song carries surprisingly far in a dense forest. Like most birdsong, this accomplishes two tasks simultaneously. For one, it signals to other males to stay away, the male wielding his song to establish a territory of a few acres– so the male singing above me likely has his eyes set on a nest site not far from our Visitor Center.

But it also tells female thrushes he is in vibrant health and has a great nest site picked out. Within days of his territorial announcement, a female initiates their pairing, enticing him to chase her in silent circular flights only a few feet above the ground. 

The bird itself is strikingly handsome. About the same size as its robin cousin, it sports a reddish-brown coat on its back, but wears a bright-white vest speckled with large black dots– the contrasts are beautiful. Many websites describe it as being “potbellied,” which is cute, and this feature helps distinguish it from its close relatives veery and hermit thrush, none of whom have dots (or songs) quite as striking as the wood thrush.

Wood thrushes are omnivores, feeding mostly on leaf-litter invertebrates and fruits from shrubs. Their summer diet includes adult beetles and flies, caterpillars, spiders, millipedes, ants, and more, and snails and salamanders are occasional prey as well. These are also the foods parent thrushes stuff into the gaping maws of their nestlings.

By the late summer and early fall, however, the thrush shifts its diet to fruits– something robin do too. They especially crave fatty fruits that help them bulk up (and get even more potbellied) for their exhausting southern migration. So in this season, they are seeking out the fruits of woodland shrubs, vines, and wildflowers like spicebush, fox grape, blueberry, holly, elderberry, jack-in-the-pulpit, Virginia creeper, pokeweed, dogwood, black cherry, and black gum. Poison ivy, bless its heart, produces splendid fall fruits that are avian magnets.

Happily, our forest is loaded with these fruits, so wood thrushes are common here. 

A creature of the interior forest and an important indicator of forest health, the thrush has become a symbol of the vanishing American songbird; one study estimated that its population has declined 62% since 1966 in eastern North America. Forest fragmentation is often cited as a chief reason for its decline, as it requires more than small suburban woodlots, and fragmented forests offer fewer places to escape predators. The brown-headed cowbird, a social parasite that lays its eggs in other birds’ nests, will stay out of deep forest interiors, but can easily find thrushes in smaller forests– and lay its eggs in the nest, its larger nestling outcompeting smaller baby thrushes for parental attention.

It’s also a victim of being migratory. While North American forests are fragmenting, Central and South American forests– its winter home– are disappearing, so, like many birds, the wood thrush is being hit at both ends of its migration.

But the first time I hear one at the Center in the spring, I stop and savor the sound: the gates of heaven have just opened. 

By Mike Weilbacher, Executive Director

Bicycling with Butterflies

Author, educator, and “butterbiker” Sara Dykman observes a monarch sipping nectar on goldenrod during her epic 10,201-mile bike trip as she followed the butterfly’s migration.

Sara Dykman did something that no other human on this planet has ever done, or even thought to do. In 2017, she followed the entire migration route of monarch butterflies from their overwintering spot in Mexican mountains, north to Canada as far as monarchs go, and back to Mexico. Over a full year, she followed the butterflies.

On a bicycle. By herself. Logging 10,201 miles, to be exact. (That’s only like 40 miles each day.) Just amazing. And on a 1989 refurbished bicycle carrying 70 pounds of equipment. 

“Butterbiking,” she dubbed it, and rest assured no other person ever thought to accomplish such a remarkable feat. Happily, she turned her adventures into a book, “Bicycling with Butterflies” to share her story with us. On Thursday, April 14, at 7:00 p.m., Sara virtually visits the Center as part of its spring Thursday Night Live series. “Bicycling with Butterflies” is a free lecture; register for the event to receive the Zoom link. 

In an email conversation last week, I asked her why she did this unique feat– and how she keeps her answer to the “why” question fresh, as I am only the latest in a long line of thousands of people who have asked her this.

“I started biking with butterflies,” she told me, “to have an adventure and learn about the monarchs, but the more I learned, the more I realized that the monarchs needed me to be their voice. My tour became a publicity stunt to catch people’s attention and help them learn that the monarch’s migration could disappear if we don’t all plant habitat, especially milkweed, which is the only food source of the monarch caterpillar. And yes,” she continued, “it can get old answering the same questions, but that’s kinda the point. I just remember that every question can lead to another person noticing monarchs and possibly creating habitat to help save them.”

In her book, she recounts another question she was asked repeatedly, starting off in Mexico, “Estas solas?” people would ask. “Are you alone?” She told me that “I’ve turned this question into a joke. I always answer it by saying I wasn’t alone. I was with the butterflies.”  

At the moment, there are no monarchs in Philadelphia– yet. As Sara will recount, monarchs overwintering in Mexico fly into Texas, exhausted, and lay eggs on milkweed plants emerging there. Those next-generation monarchs push further north, so it may be several generations before we see them in late spring, early summer. But monarch populations have been plummeting in recent decades, threatening this unique migration phenomenon. 

“Monarchs have seen a downward decline,” she said, “mostly because of habitat loss and climate change.” Midwestern farm fields are routinely sprayed by herbicides that remove “weeds” like milkweed, and as milkweed populations drop, monarchs have been declining too. The butterfly is hit at the other end of its migration, too, as logging in Mexico’s mountains compromises the fir forest where they spend the winter. Of course, climate change upends their life cycle across all of North America. 

Climate change worries her “with every ounce of my being. The earth has found this incredible balance. The monarchs arrive (in Texas) just as milkweeds are emerging, that alone feels impossibly perfect. Then you think about the wind, rain, weather, every system really. They are all connected to give monarchs and their neighbors what they need. As the climate changes, this balance will be destroyed.”

As she met people on her butterbike five years ago, she was also routinely asked whether or not monarchs needed to be saved. I wondered if people were still asking that or has the needle moved on their story? “Sure, I think the needle is moving,” she responded. “People are starting to share their yards with their more-than-human neighbors, and more people than ever know about monarchs and their plight. But we need examples of new ways of living on every street in every town, because until we learn to share the earth the monarchs won’t be safe. On my tour, it was when I stayed with people that were planting gardens and sharing that I found the most hope. I think the monarchs are amazing because they give us a first step to helping the planet. All you have to do is grow a native garden.”

As we ended our exchange, she offered, “Monarchs are so generous. They will visit even a small garden (even a potted plant) if you give them the opportunity. They will help you be part of an adventure. They can be your teachers too, because they ask you to slow down and notice the world around you. And that world is really, extraordinarily wonderful.”

Join Sara on this adventure Thursday night at 7:00 p.m. and meet the world’s one and only butterbiker.

This week in climate. “Why are we talking about anything but climate change?” wonders Mary McNamara, culture columnist and critic with the Los Angeles Times, in a scathing op-ed piece. “Our ability to lower atmospheric temperature has thus far been flung to the four (now regularly hurricane-level) winds, because a few of us are making too much money from fossil fuels and the rest of us are busy weighing in on things like ‘cancel culture’ or what the film academy should do with Will Smith to notice that we are boiling ourselves to death.” She opined, “The first thing we need to do is stop using the term ‘climate change.’” It’s a climate crisis, she says, and of course she is dead-on.

By: Mike Weilbacher, Executive Director

The Unraveling of the Red Knot

 

The red knot is one of the region’s most extraordinary birds, facing one of conservation’s biggest threats, but sadly flies under the radar of too many people. Too few of us have heard of the knot and fewer still know its story. But on Thursday, March 31 at 7:00 p.m, we’ll offer you a unique opportunity to dive into this incredible story.

A nine-inch-long sandpiper with a terra cotta belly, the red knot makes one of migration’s longest runs, flying 9,300 miles each spring from Tierra del Fuego at the bottom tip of South America to nest above the Arctic Circle in the spring. 

And somewhere around Mother’s Day, the exhausted birds– their gas tanks nearing empty– land on beaches along the Delaware Bay, looking for a critical food source to fuel them on the rest of their journey north. The famished birds need food rich in fats and that’s where the horseshoe crabs come in.

In one of nature’s best-timed events, horseshoe crabs, those prehistoric living fossils that have lumbered across ocean bottoms for 450 million years, haul themselves onto beaches. Large females usually have an entourage of smaller male hangers-on to mate and lay eggs in the surf. Each female lays 80,000 eggs, each a small green BB. They especially emerge in the full and new moons of high tides at night, a spectacle worth seeing in itself, as Delaware Bay is the single largest concentration of mating horseshoe crabs on the planet. (Bet you didn’t know that.)

So just when red knots and other migrating shorebirds need fat-rich food, Delaware Bay beaches are loaded with fatty crab eggs roiling in the surf. So the shorebirds enjoy a raucous debauchery of nonstop feeding, filling up on the eggs that give them the energy they need to finish the trip.

Many other shorebirds join them in this feast, including other sandpiper species like dunlins and sanderlings, plovers, ruddy turnstones, willets, and more, not to mention laughing, herring, and black-backed gulls, plus terns. 

It is a sight to behold. Arrive at low tide, and the beaches are crammed with shorebirds, gulls, and terns cheek-to-jowl in a frenzy of feeding, the cacophony of gulls impossibly loud; arrive at nighttime high tide, and the beach is chock-a-block with horseshoe crabs. It is a naturalist’s nirvana. On one visit last year, I easily spotted a huge turkey vulture inexplicably sitting amidst the gulls, quietly munching on dead horseshoe crabs while the gulls noisily fought over eggs. I’ve even seen bald eagles sitting on the beach at low tide at this time of year too, their size standing out among the Lilliputian shorebirds. 

Call it sex and gluttony on the Delaware Bay: the horseshoe crabs engaged in lusty orgy while the shorebirds engorge themselves on the fruits of the crabs’ labors. 

But this extraordinary confluence of natural history events is depressingly endangered. While horseshoe crabs have been used for fertilizer since the Lenape days, in recent decades the over-harvesting of the beasts for fertilizer, bait, and even medicine (the crab’s blue copper-based blood is useful to researchers) has greatly depleted their numbers. With fewer crabs emerging in the surf, knot numbers have plummeted, and bird experts are terrified we will lose the race of knots that engages in this long-distance feat. Over the last 20 years or more, there have been fierce battles raging over the allowable number of crabs to sustainably harvest, arguments leaving no one happy, neither biologists nor fishermen. And because three states border on the bay, the knot’s situation becomes even more entangled.

For the last 25 years or more, Dr. Lawrence Niles has been leading national efforts to call attention to the plight of both red knots and horseshoe crabs, and has been featured in many TV and radio news shows over the years. He is our very special guest on Thursday, March 31 at 7:00 p.m., as part of the center’s popular Thursday Night Live series of free virtual lectures. Simply visit our website to register for the event

Niles has had a front row seat on the red knot story, spending two decades as chief of New Jersey’s Endangered and Nongame Species Program, where he works on other species like piping plovers, and in 2006 started his own company to pursue independent research and habitat restoration in the Delaware Bay and elsewhere. He is also a founding member of the Horseshoe Crab Recovery Coalition and on the board of the National Shorebird Council and Western Hemisphere Shorebird Reserve Network.  

“Over the last year,” he said, “we have built the Horseshoe Crab Recovery Coalition to fight the wasteful killing of horseshoe crabs for bait and at the hand of multinational corporations for their blood despite an effective synthetic alternative.” On Thursday night. He will “describe new work on the ecological significance of horseshoe crabs, showing that their importance is far greater than eggs for shorebirds. At their natural levels, he concluded, ”they are a foundational resource for coastal ecosystems.” 

It’s a critical conservation story for the region, and I invite you to join me for Thursday Night Live. See you then.

This Week in Climate. After a two-year pandemic hiatus, the world’s youth are returning to the streets for climate strikes from school. Last week, more than 700 protests worldwide were held on Friday, according to Friday’s for Future, the climate strike organization that sprung from Swedish teenager Greta Thunberg’s solitary school strike and vigil at the Swedish parliament in 2018. It’ll be interesting to see where this goes. 

By Mike Weilbacher, Executive Director

The Amazing Monarch Migration: A Status Report

How are this year’s monarch’s doing? Join us and National Monarch expert Dr. Chip Taylor for our free, virtual event to find out.

The monarch butterfly, that large insect perfectly decked out for Halloween– or a Flyers game– in its orange and black cloak, undergoes one of the most extraordinary migrations in the animal kingdom. Butterflies across America and even Canada.

The monarch butterfly defies logic, for embedded in a small collection of nerve cells generously called a brain is a GPS directing the insect to fly from Roxborough all the way to a mountain valley near Mexico City, where it joins every other monarch from east of the Rockies (western monarchs head to the Pacific coast). As you read this, monarchs across the eastern US and even Canada are flying south, many along the eastern seaboard; most are near or even in Mexico already.  

Once in Mexico, they gather in large groups to coat fir trees with millions of their bodies, a remarkable sight visited by thousands of eco-tourists annually. The butterflies wait out the long winter, living five months—Methuselah territory for an insect.

In early spring, they begin heading north, make it into Texas, lay their eggs—and die. It takes another generation or two for monarchs to make it back to Pennsylvania, not until early summer. So the butterflies hatching in my garden will start flying more than a thousand miles to a place they have never been. How’s that for Mother Nature’s planning?

If you’d like a treat, drive to Cape May point soon and watch clusters of them funneling down New Jersey hop across the Delaware Bay to get to the mainland and continue their journey south. 

While it’s remarkable that an insect can make this migration, I’m saddened to report that this phenomenon is endangered as monarch numbers have plummeted in recent years, compromised by climate, pesticides, Midwestern “milkweed deserts,” and over-logging in Mexico. 

So how are this year’s monarch’s doing? How is the insect holding up? Should it be declared an endangered species?

We hope to answer this question on Thursday, October 21 at 7:00 p.m. with our Thursday Night L!VE presentation, “The Monarch’s Amazing Migration: a Status Report.” National monarch expert Dr. Chip Taylor, founder and director of Monarch Watch, the organization that has helped place 35,000 monarch waystations across the country, joins us from his Kansas base to share the creature’s story and its status. Monarch Watch started in 1992 as an outreach program dedicated to engaging the public in studies of monarchs, and is now concentrating its efforts on monarch conservation. 

“In real estate,” Dr. Taylor says, “it’s location, location, location. And for monarchs and other wildlife it’s habitat, habitat, habitat. We have a lot of habitat in this country, but we are losing it at a rapid pace. Development is consuming 6,000 acres a day, a loss of 2.2 million acres per year. Further, the overuse of herbicides along roadsides and elsewhere is turning diverse areas that support monarchs, pollinators, and other wildlife into grass-filled landscapes that support few species. The adoption of genetically modified soybeans and corn have further reduced monarch habitat. If these trends continue, monarchs are certain to decline, threatening the very existence of their magnificent migration.” 

Female monarchs are exceptional botanists, laying their eggs only on one family of plants, the milkweeds. She tastes plants with her feet, laying eggs on the undersides of milkweed leaves. Caterpillars hatch from eggs, and immediately begin munching on milkweed—the only food they are adapted to eat. The creatures have evolved to take the noxious chemicals found in milkweed sap and use it to make themselves—both caterpillar and adult—bad-tasting for any bird that may try to eat it.

A very clever “Got Milkweed?” campaign was started years ago, and more and more home gardeners like me began planting milkweed– and the Schuylkill Center has been selling milkweeds for years.

To address these changes and restore habitats for monarchs, pollinators, and other wildlife, Monarch Watch is initiating a nationwide landscape restoration program called “Bring Back the Monarchs.” The goals of this program are to restore 20 milkweed species, used by monarch caterpillars as food, to their native ranges throughout the United States and to encourage the planting of nectar-producing native flowers that support adult monarchs and other pollinators.

This program is an outgrowth of the Monarch Waystation Program started by Monarch Watch in 2005. “While these sites, mostly habitats created in home gardens, schoolyards, parks, and commercial landscapes, contribute to monarch conservation, it is clear that to save the monarch migration we need to do more,” Taylor said. “ We need to think on a bigger scale and we need to think ahead, to anticipate how things are going to change as a result of population growth, development, changes in agriculture, and most of all, changes in the climate.”

According to Taylor, we need a comprehensive plan on how to manage the fragmented edges and marginal areas created by development and agriculture, since it is these edges that support monarchs, many of our pollinators, and the many forms of wildlife that are sustained by the seeds, fruits, nuts, berries, and foliage that result from pollination. “In effect,” Taylor argues, “we need a new conservation ethic, one dealing with edges and marginal areas that addresses the changes of the recent past and anticipates those of the future.” 

Dr. Chip Taylor has been pioneering in butterfly conservation for decades. Meet him by joining me in a Thursday Night L!VE virtual lecture this week. Register for the free event.

By Mike Weilbacher, Executive Director 

Window Strike Season

A towel, some gloves, and a cardboard box are all you need to help rescue window-strike victims like this black-throated blue warbler.

It’s fall migration season- do you have your bird rescue kit ready? 

During the summer, if you come across a bird on the ground that can’t fly, it’s often safe to assume that bird is a baby. But during spring and fall migration, birds that are found on the ground that do not fly away are frequently adult migratory birds that have struck a window or become disoriented and are in need of human help. 

Many migratory birds do most of their travelling at night, when they use the light from the moon and stars, reflections from bodies of water, and even particular sounds to help them navigate their way to their winter grounds down south. Bright lights of urban areas, especially those that extend high into the sky such as skylights and skyscrapers, are particularly dangerous. The most common places to find these birds will be early in the morning on the sidewalk below tall city buildings, but you may find them sitting below the windows of your home and business as well. 

Remember- the head and spinal trauma that can result from colliding with a window at high speed is a medical emergency! Common signs of collision include: looking “puffed up”, squinting eyes, squatting down instead of standing upright, and neurologic signs like trembling or a head tilt. 

Rapid action is so important to the bird’s survival.

Here’s what to do if you find a bird on the ground that you suspect may have hit a window. First, have a “rescue kit” ready so you can act quickly if you see a bird in distress. Keep the following items handy in your car or bag: a paper bag or a small cardboard box with a lid, a tea towel, old t-shirt, or small blanket, and a pair of gloves. They are small things to have, but they can help to save a bird’s life! 

  Be sure to approach the bird slowly and from a safe angle. Even if a bird is stunned, they may still have limited ability to fly so we don’t want them to fly into traffic or back into a window or building again! As soon as you are close enough, drop a small towel or cloth down over top of the bird, completely covering the head and wings. This will help to reduce stress and keep the bird calm. While wearing gloves, pick up the bird in the towel and place them in the paper bag or cardboard box. Fold the top of the bag down and secure it with a paperclip, or close the lid of the box. This is very important- the bird is likely in shock, and needs to be kept as quiet and stress-free as possible during transport. 

As with any injured animal, do not try to give them food or water. A bird with head trauma could drown or choke if they can’t properly hold up their head, and eating improper food items can cause serious medical issues. Keep the bird in a quiet, dark place and transport them to your closest wildlife rehabilitation centre as soon as possible. 

Migratory bird populations are declining all over the world due to climate change, habitat destruction, and human-caused conflicts like window strikes. Keep your eyes open and your rescue kit ready, and be a hero to the birds!

By Rebecca Michelin, CWR | Wildlife Rehabilitation Consultant