MAY

Return from the Tropics

I WALK OUT THE FRONT DOOR, and I cannot believe the sight before me: a male rose-breasted grosbeak quietly feeding at the fly-through. I never see them this early, usually noticing their presence in the second or sometimes even the third week of the month. I watch in amazement as the brilliant black, white, and rose-colored neotropical bird cracks sunflower seeds at the edge of the feeder. Why is he alone? Perhaps the other birds—cardinals and chickadees—flew off frightened when I opened the door, leaving him to feed in peace. He sees me and doesn’t seem to care. Has hunger from migration driven this normally shy bird to ignore my presence? I continue to watch. I can hear him shelling the seeds as the chaff is sifted from the corner of his massive beak and drifts away in the gentle morning breeze.

On this first day of May, as I stand in my doorway at the threshold of the breeding season, I know it will seem as if, in the single beat of my heart, the entire spring has slipped away. Something about this time of year makes it go by so quickly. It seems everything about May is fast. I can see it in the intensity with which this beautiful grosbeak is feeding. This famished neotropical bird desperately replenishes itself on this cool May morning because it can still get cold in early May, and the grosbeak will need every calorie it can consume. Weeks remain before the abundance of insect life that it will glean from the foliage is readily available. My oaks won’t be fully foliated until the end of the month, and by then, the females had best be getting on with their nesting if they are to get that critical early start. The young need time to grow before heading south at summer’s end.

The grosbeak begins its race against time while still at its wintering site. It heeds the call to gain strength and consume calories as the southern hemisphere angles away from the sun. Its migration will not be easy, and it has to move fast. The grosbeaks that nest in my neck of the woods have an added challenge during migration—much more so than those nesting in the western part of the United States. The grosbeaks arriving here must cross the Gulf of Mexico from their wintering sites in Central America and northern South America. Grosbeaks headed for points west of the Mississippi usually migrate over Central America and up along the Texas coast, avoiding the ocean crossing.

If there is a favorable wind, their journey may involve up to twenty hours of nonstop flying. Anything longer, which can occur without a tailwind, is too long and will result in death. Most similar-size songbirds fly at an average approximate speed of twenty-seven miles per hour. Yet the grosbeak must maintain a greater speed if it is to survive the crossing because the route that eastern-breeding grosbeaks take over the Gulf of Mexico is no less than six hundred miles. So you can see how challenging the crossing is for those birds that are headed east. I’ll remember the grosbeaks’ challenging migration the next time I complain about a long airplane flight.

I’ll have maybe three weeks to enjoy the grosbeaks at such close range; after that, they abandon the seeds at the fly-through and begin nesting. Grosbeaks have unusual nesting habits: the males incubate the eggs and even sing while doing so, and they help raise the young. The female grosbeaks also differ from the norm; they are among the few female songbirds breeding in North America to perform a territorial song. Ornithologists talk about other odd behaviors, such as the unique intimate communication between the male and the female during the nesting phase. The literature is filled with accounts of closed-bill singing between males and females. It is a song so soft that it can be heard only by using listening devices at close range, but it is said to be beautiful beyond description.

Elusive and shy by nature, rose-breasted grosbeaks spend most of their time high in the canopy of the woods. It is only during the first few weeks of May and within the first days after their arrival that they share their beauty and allow themselves to be seen with any regularity. This is often the case for many of the summer-breeding neotropical species. Wood warblers are the perfect case in point. We can readily see them during spring migration, but by June, they are lost within the foliage, and we must look for them specifically. Beginning in March with the arrival of the very first spring birds, pine warblers turn up within the towering white pines throughout the region. By late April, I start to see more warblers, except now there are several different kinds. Yet not until the second week of May do huge numbers of them begin to appear. Now I see yellow-rumped warblers by the dozens along streams and woodland edges and even on suburban lots. They gather in clusters, flitting about the branches, often with black-throated green, black-throated blue, yellow, and Canada warblers. Later, around the third week of May, American redstarts become more numerous and complement these groups.

The flocks, or loose associations, comprise a random assortment of warblers. It is not as if yellow-rumped warblers associate solely with black-throated blues or black-throated greens only with yellow warblers. Rather, maybe, because of food availability, departure dates, or population levels, I seem to see certain warblers together more often than others. During migration, I watch for warblers just about any place with a mixed habitat.

Here at home, I like to look for warblers at the back of my woodlot, where the stream, the meadow, mature woods, secondary growth, and suburban yards all sort of meet. Back there, I find two members of the warbler family, ovenbirds and northern waterthrush, feeding on the ground near the stream. Above the stream, black-throated green, Canada, and yellow-rumped warblers search for insects by flitting along the overhanging branches of maple and black birch. Above them or just below the far upper canopy and still above the stream, American redstarts hawk insects, while black-and-white warblers work the trunks of larger trees in nuthatch fashion.

Among all the diversity, I can’t help but see the beauty in the setup, each bird having its place and feeding on different things or in different places for similar things. Above all, each bird benefits from the other and from the other’s location: the entire group gains better surveillance along the stream. This coming together of “many eyes” explains the grouping of these warblers while they feed at stopover sites during their long journey north. It is all about strength in numbers. It simply improves the odds of at least one of the birds in the group spotting the advance of a lurking predator.

There is a mix of so many different types of warblers because they care less for habitat preferences while migrating. During migration, a yellow-rumped warbler that normally prefers a conifer habitat has little concern for such specifics as tree species; rather, it takes advantage of the best available site it can find from above. Consequently, you have sites, such as Central Park in Manhattan, that entice warblers of all kinds into what is not a typical place where most would choose to be. They see the large patch of green in a region of nothing but concrete urban sprawl, and they know it is their best choice for the stopover. The kinds of warblers found together have more to do with the individual timing of those species’ migration than with the habitat in which they appear, but you probably won’t ever see a riparian-loving waterthrush feeding high up on some branches either.

While at the stopover, the warblers rest and refuel. Typically, they land before dawn, get their needed rest, and then start feeding after sunrise and on into the morning. By late evening, they have replenished themselves and are ready to take to the skies again. By migrating at night, they are able to feed during the light of day. Although having that daylight to find food is important, there are many other reasons why warblers and other species migrate at night.

Initially, people believed that birds needed the stars to find their way to their breeding sites, but through years of incremental contributions to migration research, we now know that many more reasons exist, including the better flying conditions that birds experience at night. For example, at night, they have less risk of hyperthermia from flying in direct sunlight during higher daytime temperatures. Higher temperatures and sunlight increase water loss, posing the threat of dehydration, which requires the bird to stop for water. In addition, heat from the sun creates updrafts and instability in the air, which often result in turbulence. By flying at night, the birds face less turbulence, and they can achieve flight speeds far more efficiently, thereby consuming less of their precious energy reserves.

For my red-shouldered hawks, however, daytime migration works best because hawks migrate by rising with the thermals and then gliding and flapping as far as possible until they can catch another rising mass of warm air. This method of migration is highly efficient for the hawks, which would quickly become exhausted in continuous regular flight. They are restricted, though, by atmospheric conditions and overall weather patterns. Hawks must wait for thermals to form, which, in this region, usually doesn’t begin to occur until about 10:00 a.m. On a good day, a hawk will get between four and nine hours of soaring time. Some of these thermals can elevate the hawk about six hundred feet in an hour, providing an optimal glide ratio from the peak of the thermal. They can average 25 miles in an hour, while traveling 225 miles in one full day of soaring. When I worked at Mount Tom in Holyoke, Massachusetts—a well-known hawk-watching site during their migration—we waited for the classic weather conditions to arrive in the form of a backdoor, high-pressure cold front. On those days, hundreds of hawks migrated ahead of the cold air pushing down from the northeast. In the spring, hawk migration was far less spectacular because they worked their way back north using a different weather pattern.

Whether by day or night, migration has to be one of the most fascinating topics in ornithology. For me, the migration period is also the most inspiring time of the year. And for all that we have learned, so many aspects of migration still remain poorly understood. It may happen twice each year, but the mystery of migration never ceases to intrigue me. How does a hummingbird, weighing no more than the nickel in your pocket, make it here all the way from Central America through all kinds of adverse weather? How can the warblers I find by the stream fly nonstop over ocean waters for more than a day? The fact that a tiny warbler weighing less than fifteen grams, or about as much as a ballpoint pen, can cross a vast portion of the open sea flying nonstop for almost two days is utterly amazing. It is equally difficult to grasp how the tiny bird can find its way over thousands of miles to return to an exact site.

Theories about how and why migration evolved are too numerous for me to keep track of, but I do know that, regardless of which new theories arise, the availability of food will always be a significant part of any explanation. Birds migrate to attain the advantage of available food, and this has to be one of the basic foundations of how birds developed the instinct to migrate. The abundance of food also directly affects their rate of reproductive success.

Our understanding of migration has accumulated slowly over time, and, as is the case for all fields of science, we have arrived at present-day conclusions by trial and error. Interestingly, most of the theories—even some of the oldest—have proved to be at least partly correct. Certainly, however, some of the most ancient ideas on migration were wrong. For example, Aristotle believed that instead of migrating, birds simply transformed into different species. Another common belief was that birds went to sleep at the bottom of the ocean. Eventually, the theories became more sophisticated and closer to reality.

During the last few hundred years, people began to identify strategies used by birds that we now know have some substance. Research considered birds’ use of stars or the sun for navigation. In recent history, ornithologists started to wonder whether a combination of different strategies might explain how birds find their way to their destinations. One early theory suggested that birds had an innate or genetically programmed sense of time and distance that would tell them to fly for a set period, change direction, and fly for another period. However, this theory had many dead ends.

By the 1970s, attention turned to magnetism. This theory had been played with, but not until recently were better research and greater focus applied to the use of electromagnetic fields to explain how birds found their way. A serious look at magnetism began with the work of two German researchers, Roswitha and Wolfgang Wiltschko, who published convincing proof that birds used the earth’s electromagnetic fields to navigate. Subsequent studies confirmed their findings, and the premise developed from there.

Researchers soon applied this knowledge to the understanding of other theories. For example, they found connections between the use of electromagnetism and the older theories claiming that birds oriented their direction based on the sun or the stars alone. Researchers discovered this link between stellar magnetism, solar magnetism, and electromagnetism by studying migrant birds before they departed, noting that birds took cues from the polarized light of the sun along the horizon. This important discovery brought us to where we are today—that is, our basic understanding that no one single answer exists but rather combinations of them. Birds’ migration occurs due to a variety of factors, including stellar magnetism, solar magnetism, electromagnetism, and even olfactory stimulation. All are integrated to allow birds to find their way (though not all birds use all of these strategies). Most important, migration is plastic. Evolution has not completely programmed the bird; rather, it is capable of making decisions while en route to adjust for conditions along the way, thereby enabling it to arrive safely at a given location using a variety of cues. In other words, birds combine instincts and observations to arrive at a precise location in much the same way that a human pilot uses automation and his or her own reasoning to fly a commercial aircraft.

Knowing these facts about migration makes the sight of my first rose-breasted grosbeak of the season even more satisfying. I also understand how this bird can eat seed after seed for what must be twenty minutes since I first laid eyes on it after opening my front door. I honestly think this bird has consumed about a pound of seeds in this one visit. I swear I saw a noticeable pile when I came out here, and now it looks like I’ll need to restock the feeder shortly. I guess if I had just traveled a few thousand miles, I might be famished, too.

A few yards from the grosbeaks is where the robins have nested in the white spruce for two years now. Each spring, I watch the pair construct the nest, and I cannot help but wonder whether they winter locally or, like the grosbeak, have traveled hundreds of miles through the night sky to build their nest of grass and mud in my white spruce. I wonder how far they might have journeyed, through what kind of weather, over what kind of terrain, and past how many predators. Thinking about their journey and the miracle of migration captivates me. Reluctantly, I turn my back on the grosbeaks, walk away from the spruce containing the nest, and get into my car with the intention of spending the day indoors at work. On the drive to work, I will have only enough time to reflect on how quickly the spring passes. But I’ve scheduled two days off next week to search for spring migrants.

AFTER PLANTING A ROW of green peppers in my backyard garden, I decided to sit on the bench by the doghouse to see how the bluebirds were doing today. The male bluebird immediately flew over to exactly where I had been, grabbed something I’d stirred up in the soil, and returned to his perch on a branch a few feet above the nest box. Quite often, he does not wait for me to finish my work in the garden; he flies to a tomato stake right beside me and then drops down before leaving quickly with a precious morsel. This tameness or absence of fear is, in part, what makes the bluebird such a likeable companion to the gardener. I am certainly not the exception in my positive feelings for bluebirds.

I thought the eggs might have hatched because the female has been around more lately. After watching the box for quite some time, however, I believe she is still incubating. Neither parent has made repeated forays to or from the box. Occasionally, the male puts his head into the entrance hole with a beak full of food and then flies back to the garden. He has done this infrequently, so he must be feeding the female. If the chicks had hatched, he would be much busier, flying back and forth with food for them. I think it will be another few days before she is through sitting on the eggs. On average, it takes about thirteen to sixteen days for the eggs to incubate.

While sitting there, I never once saw the female leave the nest box unattended; the male always entered the box immediately after she departed. On several occasions, the male would fly to the box, perch on the roof, call out briefly, and then fly back to the garden. It seemed he wanted to let the female know that he was available to watch the eggs in the event that she might need to leave again. They seemed to work beautifully together now that they were past the courtship phase, when the female played a little hard to get.

On my way back to the house, a gray catbird flew low across the driveway, over my front garden, beneath the robin’s white spruce, past the fly-through, and into my side woods. The sight of it brought back memories of Heather’s childhood fort. When she was just eight years old, she often hid in her secret fort, which was tucked away back in my side woods near the garden. I remember the astonishing moment when I witnessed a flock of gray catbirds land high up in an oak tree. I was there alone to fix the roof. They rested for only a minute and then scattered with the spring wind—all but one. It remained, then flew down from the high perch and landed on the flag post of Heather’s humble fort.

The catbird circled the fort several times. Its tail twitched in nervous curiosity, and its eyes burned bright with intelligence. It didn’t take much for me to assume that it might have just arrived from the far south. I lay on my back in the fort, peering up through the open slatted roof, and watched the clouds change shape and their soft hues change color in the May sky. Had I just witnessed this bird’s return to its breeding site? The shy but vocal catbirds have captured my attention.

On returning a few days later, I found the bird singing on a low branch above the nearly impenetrable thicket surrounding Heather’s fort. The fort acted as the perfect blind, and during the course of a few weeks, I observed the catbird with its mate as they built a nest and raised their young.

Consequently, I eagerly anticipate the arrival of more gray catbirds and listen carefully for their familiar songs each day. Catbirds usually make an appearance about the second week of May. When they do get here, they will have traveled thousands of miles. Their wintering range extends from the Gulf Coast into Mexico and Central America.

Last year, I found a pair’s nest in the row of spruce near my garden. I noticed the pair flying to and from the spruce, making the nesting site obvious to me. Like the bird at Heather’s fort, this male sang quietly whenever I approached. I was certain that he had a nest hidden there when he also gave the meow call, for which the bird is named. Catbirds give the meow call when alarmed.

I had no fort from which to observe this nest, but I realized that there were other ways to see catbirds. They are very fond of grape jelly and will visit any jelly feeder on a daily basis. Catbirds will devour raisins, sliced strawberries, and suet with fruits in it. In fact, fruits make up the bulk of their winter diet and almost half of their consumption during the summer.

Although watching catbirds at the feeder cannot compare to actual field observation, it is much more convenient. I don’t think I want to crawl into any more kids’ forts, and if I do, what are the chances of a fort being in close sight of a catbird’s nest? Sometimes, the simple secrets of nature are revealed to us solely by chance.

FINALLY, THE WARM SUMMER-LIKE weather has arrived, and with it the big push: the thousands of long-awaited neotropical migrating birds. Now they fill the mornings with song, and the symphony will grow stronger each day. So today is the day I rise early and venture out before sunrise to experience the exultant return of thousands of these intricately colored birds, as they rest and forage within the unfolding galaxy of new green leaves.

And to think it all began way back in February with the return of the first redwing blackbird and continued with the sighting of grackles flying overhead. It got everybody’s attention when the robins appeared on our lawns, and it really turned heads skyward when the honking of a skein of geese revealed a flock flying north across the sunset. Then there were the reports, the sharing of sightings, my friend Karen’s first phoebe, and my first sighting of that rose-breasted grosbeak. Nearly all migrants are now present and accounted for. Migration is in full force.

I finally open the window beside my bed and keep it open during the night. It was mid-October when I last slept with it open. The open window allows me to hear a chorus of spring peeper frogs ringing loudly from the vernal pools. I fall asleep more quickly when it’s open, entranced by the sweet smell of unfolding ferns and the awakening earth carried in with each gentle warm breeze.

I wake up the next morning to the cheerful song of the robin. It must be the male whose mate is on the nest out front in the white spruce. His song is rich, pure, and without imperfection. I lie in bed listening. The song is loud, and it seems as if the bird’s breast is my pillow.

When something startles the robin, the singing stops, and I become aware of the time. I think I’m dreaming my morning away, but I look over at the clock and realize there is still plenty of morning left. I leave the house immediately. It is early—predawn early. The sky is without color, and the fading darkness hangs on as I walk down Buchalter Road, cross Westerly Drive, and enter the woods behind the houses there. Red-tipped stakes mark a thin trail snaking through these woods. It charts the course of a possible extension of Buchalter, which was later abandoned as infeasible.

In the spring, I meander through these woods. As warblers come, days get warmer, and birds build nests, I wander through the saplings to see what I can see. You have to leave the trail to get to the saplings, which grow not far from Heather’s Meadow and all along Treasure Run. Here I’ve discovered the familiar sound of leaves being tossed to and fro. The sound runs through my mind, which searches for an explanation: could it be an eastern towhee or maybe a wood thrush? A brown thrasher? I make my way slowly through the thicket, hoping for a chance encounter with the last of the three—a brown thrasher. But instead I find a woodcock—a most peculiar and unexpected sight.

I’ve never seen one so close. I don’t know what it is doing here; I’ve never seen them in the neighborhood woods before. Still, I consider myself rather lucky to be so close to such an elusive species. Because it is preoccupied with something in the leaves, I decide to see whether I can get closer to it. I notice an old, rotting plank of wood lying over dry leaves. Walking on it ought to allow me to approach the bird quietly. I get to within thirty-five feet of the woodcock. Hiding behind a large oak that towers over the saplings, I begin to watch the peculiar bird working the leaves until it unexpectedly waddles a few yards toward the stream and bursts into flight. It flies along the stream, rounds a bend, and is out of sight.

I follow the stream to where the bend is, but I don’t see the woodcock anywhere. I decide to find a comfortable place to sit and simply enjoy the soothing sound of flowing water. I lean up against an old maple, whose sturdy trunk hugs the bend and whose large, twisted roots reach out in all directions. With my knees bent and my boots dug in deep along the bank, I’m able to secure a resting place without sliding into the stream. I can’t see into the water because it glistens like a million diamonds in the late-morning light. Soothed by the warm sun on my face, the laughing gurgle of the stream, and the sweet notes of the warblers in the canopy above, I drift off into a light sleep.

My stream of consciousness is fragile. Behind my closed eyes, I see dancing, shifting patterns of light, and an indescribable red—the sun or energy itself—penetrates my eyelids. When I open my eyes, I realize that a moment or two have passed, the sun is farther west, and I’ve blended in, I think. Taking advantage of the moment, I remain motionless and look around for birds that might have approached too close. At the edge of the stream, just a few yards away, I see a northern waterthrush. I’m careful not to frighten it.

ZOEY WAS BARKING LIKE CRAZY yesterday. I went into the living room to investigate and found her, paws up on the windowsill, yapping her sweet, foolish head off. When I looked out the window, I saw one of my resident red-shouldered hawks on the grass, wings spread a bit, with a mouse pinned beneath its talons. The hawk seemed to catch my movement behind the glass and took off with the prey dangling from its death grip. Zoey lunged at the window as the hawk flew across our view. I realized that she’d probably heard the high-pitched distress cries coming from the mouse. It must have awakened her from her afternoon nap; otherwise, I doubt she would have known that the hawk was there.

The red-shouldered hawk seems to have figured out that there are plenty of mice near the feeder because it has been hanging out there frequently. I don’t believe it is as interested in the feeder birds as it is in the mice. Now that I think of it, I don’t remember ever seeing a red-shouldered hawk pursue a bird around here. I read somewhere that they seldom feed their fledglings anything but small rodents for the first few weeks. This might explain why the hawk frequents the feeder, with its nest now full of hungry fledglings and the feeder attracting so many mice.

In fact, my yard has been downright noisy during the last few days. The raucousness begins shortly after sunrise, when the male arrives near the nest with his first rodent of the day. He calls out to the female, who responds while leaving the nest to take his catch and bring it back to the fledglings. I sometimes hear the fledglings cry out in excited hunger as their mother feeds them. They quickly settle down and remain quiet until the male returns with more food.

Each time the male flies in with food, he arrives from one of two directions: either from the front of the house, where the fly-through feeder with the mice is located, or from my back woodlot where the rocks are. Curious about what he finds beyond the rocks, I decide that today I’ll check it out. Because these hawks prefer to feed rodents to their young, it seems unlikely that he is catching them in the woodlot, where amphibious prey are probably more abundant. More likely, he is traveling through the wet woods to hunt on the other side—the wooded area behind the houses on Edgewood Drive. So I walk over to Edgewood and listen for his call notes as he approaches the nest. I count five minutes—the usual amount of time he spends delivering food to the female—and then wait, watching for him to appear at the wooded edge behind the houses.

I walk quickly back and forth, peering into two of my neighbors’ backyards, looking for the hawk. Behind the last house at the end of the street, he emerges from the middle canopy of the woods and glides to a lone tree a few yards from the edge. Unable to stand there staring into my neighbor’s backyard without somebody calling the police, I have to assume that he will keep his perch until he spots a rodent to bring back to the nest. The neighbor has let the grass grow tall in a portion of the backyard, allowing mice to thrive there.

IT IS MEMORIAL DAY, and I’m in the garden planting tomatoes. I have been watching the bluebird box closely for a while. The male has made five trips to and from the box in just thirty minutes or so. This could mean only one thing—the eggs have hatched. Now the work of finding food for the growing chicks begins. In the richness of May, food will be plentiful. Although finding food tires both the male and the female, the young will get the nutrients they need. The bigger threat comes from predation and severe weather, but I checked the ten-day forecast yesterday, and it looks as if we’ll have seasonable weather all the way through.

The chicks must have hatched very recently because only the male is collecting food. This means that the female is still brooding her young, which probably don’t have feathers yet. When he lands on the box, he peers into the hole and then goes inside. If the chicks were any older than a few days, he would not go all the way into the box, and I would hear them call out with loud, strident notes. I’m lucky that I caught them early in their development, and I can now keep a close eye on the pair as the chicks grow within the nesting box. I’ll watch them closely, anticipating the day when their young emerge into the outside world for the very first time.

In a few days, the female will leave the nest box to help the male find food for the growing chicks. Until then, the chicks depend on her brood patch to regulate their body temperature, while downy feathers begin to cover their “naked” bodies. Once this happens, the bluebirds develop quickly: in just four days, their tiny wings will start to mature; by the fifth day, the chicks will have opened their eyes; on the eighth day, their tail feathers will have appeared; and by the twelfth day, they will already weigh as much as their parents. In only two weeks, they will be completely feathered. A few days later, they will be ready to leave the nest box. Because this all happens so quickly, I’ll be lucky—very lucky—if I’m able to witness the precise moment they emerge. May moves fast.