Wood Thrush Summer

We recently passed our 32^nd anniversary of living out here in this blessed wilderness. By now we've pretty well come to understand what this place has to offer, and look forward each year to what stand-out experiences nature will be providing. Each season brings its exceptional offerings and phenomena, and it's fun to pause from our daily tasks and devote some time and attention to those exceptions. Questions we pose ourselves: What has made this summer special and different? What has been particularly bountiful in the vegetable garden? What events will we experience and remember for years to come? Is this a one-time event, or is it similar to an exceptional experience that occurred a decade ago? How do we assimilate all this?

These are simple pleasures—but they are pleasures, because we have the time and inclination to pay attention to them and enjoy them. On the evenings when I soak in the outdoor tub, I often let my mind wander over and savor this year's recent special events. Not all are joyous, of course. The gnats may have been especially pesky, or several weeks may have passed now without a decent rain, but that's all part of the flow; and we have learned a key lesson in life: the unpleasant experiences soon fade from memory, as the fine ones persist.

As I was soaking in the tub recently, in this mental mode of appreciating what Mother Nature offers, I was being regaled by wood thrush songs. I've written in this blog a few times about the fact that no avian singer around here tops the wood thrush, as to its spectacular singing voice. They have a song that constantly changes, is incredibly melodic, and literally stops you in your tracks (or hot tub reveries)—forcing you to pay homage to its call.

I've also written about how the wood thrush population is in decline in the Americas, and that we've noted fewer and fewer of them out in the woods each summer. Habitat destruction in both the United States (its summer home) and Latin America (its winter abode) threatens their existence.

After the last few years of many fewer wood thrush songs, this summer has been very special. It's literally a wood thrush summer! Not only do we hear several of them calling out, but they are much closer to the clearing this year. (The wood thrush prefers dense forest, so it's a treat when they approach the clearing.) When they are near, we can clearly discern each part of their intricate call—especially that third part: a high-pitched melodic trill that is amazing.

With so many thrushes calling at once—sometimes we've heard three or four in competition—they really provide a show! And it is a form of rivalry. I'm sure they do hear each other and try to best their rival. We can hear them pause, listen to their challenger, and respond. So what's the cause of these calls? Are they still vying for mates this late in the season? Is it just a song competition? We don't know. Sometimes it's as if they are egotistical opera stars—competing for the lead role at La Scala.

Is each wood thrush aware of how well he's doing, relative to his competition? Is each of them aware of how superior is his song, compared to the squawks and simple whistles of the titmouse? Is his aesthetic judgment anything like ours? Does he compare the complexity and beauty of his call to that of his rivals? Does he realize that he is the premier songster of this forest? I would guess that most of the beauty we perceive and the pleasure we derive are not necessarily shared by him.

He's probably just trying to become alpha bird—the most intimidating and admired thrush of the forest. I doubt that he has any comprehension of the joy he brings to our ears. I wish we could make him aware of our appreciation, but I doubt that he'd understand. Let's just call it grace.

Fidgety Fowls

I am sitting in my outdoor tub, soaking in the hot water—my attention momentarily turned outwards, to the natural world surrounding me. What attracts my observations at the moment is not the breeze wafting through the trees, or the insects calling forth, but a single bird singing from the woods up on the hill. It's a wood thrush—who I tend to regard as the top songster around here.

I hear him call out several times from a location up the slope a ways. Then he pauses, sings again, and I soon realize he's flitted to a new perch a hundred feet or so away from his initial singing post. After a few more songs offered from there, he moves again to yet another location and bursts out in song again.

I aurally follow this fidgety fowl, as he flits and sings a few more times, with no apparent (to me) pattern to his movements. Then I hear another wood thrush singing from time to time, from a more removed place deeper in the woods. Is this a rival?

So what's going on here? Why does the closer bird call half a dozen songs from each location, before flying to a new perch? I can't discern any method to his position changes. Is it random? Does he have a game plan that escapes me?

And what's the purpose of his singing this evening? Is it a mating call? Is he defining and defending his territory? Is it just an urge to sing from various perches, to see how glorious his call can be?

If he is mounting a defense of his domain, do the various singing posts he occupies define the boundaries of his realm? Is he letting the opposition—maybe that farther-off thrush—know where his frontiers lie? Maybe he's looking to expand his territory, and is testing the response of any rivals, to see how successful his feints might be. “If I cross over my boundary a bit, will the other guy take offense? Can I fake him out and claim an expanded stake?”

But maybe he's really seeking a mate. If he changes position from time to time, maybe his song will travel a little deeper into the woods from a specific perch—just enough to reach a receptive female. Maybe his song flies through the trees much more melodiously from one specific perch... more than that perch over there.

But he also may be alert to possible threats—that sharp-shinned hawk was spotted earlier today and the thrush can't afford to remain in any one location for more than a few quick calls, lest the hawk zero in on him.

How I wish I could interview this bird and pose some of these questions to him. He could enlighten me. He could clear up the mystery. That's not going to happen any time soon, so I guess I'm relegated to a solitary soaking in the tub, as I speculate on what this wood thrush is up to. So I do have other than a hedonistic purpose for spending all this time soaking in the tub: I'm conducting experiments in the natural world. This is science—not self-indulgent soaking!

Fading Thrushes

I have written before (“Wood Thrush Encounters,” 7/19/08 and “Foreign Bird Call,” 10/31/12) of how thrilled I get when the wood thrush sings out from the forest. Most species of thrush have beautiful songs, and of the handful of thrush varieties we are blessed with around here, the wood thrush is clearly the winner. Its call is melodic, inventive, artistic, and exquisite—like a Bach étude.

The bad news is that wood thrushes are on a steep decline. Their habitat—both in the summer in the US and over the winter in Central America—is dwindling, along with their population. I am keenly aware, as their gorgeous songs become scarcer in our woods, that the days we may listen to their melodies are limited.

Maybe the dwindling process is even going on very locally now. The last couple of years we have heard their calls much less often. We once were regularly regaled in early morning and after sunset with their repeated songs—never once tiring of them. Now we seldom hear them. I caught the old familiar call a few nights ago, for the first time in weeks. How it thrilled me! I stopped in my tracks and gratefully tuned in.

I wonder what will happen on the nature scene, after the wood thrush is gone—as seems rather inevitable. For a few million years the bird has filled its niche—fulfilling many more functions than simply singing for human pleasure. How will its disappearance upset the exquisitely balanced ecosystem? It will leave a hole—one that undoubtedly will be filled by an opportunist, who I'm sure will not be able to sing nearly as beautifully.

Nature, over the eons, has attained a robust yet fragile equilibrium; a sacred stability that we only barely understand. In the process, a divine natural art has been created. We blundering humans are defacing that scared art—for no good reason. We will wake up someday and face the results of our devastation—but how much will we have permanently lost by then?

Foreign Bird Call

Thrushes are our most accomplished singers around here. Their songs are complex, variable, extremely melodic, and endlessly fascinating. The three thrushes we have, in decreasing order of song beauty are the wood thrush, Louisiana water thrush, and the good ol’ American robin. Thrushes are also migrating birds, so we eagerly await their calls each spring and joyfully exclaim our first hearing. 

For years, we’ve thrilled to listen to our best thrush caller—the wood thrush—coming from various places off in the woods. They are the first to call just before dawn and again the last to call after sunset. Their song is a three-part symphony, always repeated in the same order: (1) two low stutter tones, (2) followed by three flute-like liquid notes in varying order, and (3) capped off by a high-frequency trill or tremolo. The third part comes in at least half a dozen varieties, and the bird delightfully mixes them up. I can listen to a wood thrush call out 20-30 times and he never exactly repeats his song.

This year was different, however. There seemed to be only one thrush out there in the woods, and his song was not the same as in the past. Most of the time this guy left off the first and third movements—curtailing it to singing the middle three notes. At other times he’d just sing the final trill. I don’t think it was the same bird we’ve had on the past… moreover, it was only one bird calling from out in the woods during the season. Where were the other thrushes this year? Was this a new guy—either from another territory (with another accent) or maybe a juvenile just learning the song?

Ornithologists know that America’s wood thrush population is alarmingly declining. They breed in the eastern United States and winter in Central America. In both regions, their habitat is disappearing, as forests (its only home) are cut for agriculture and other commercial uses. We feel very fortunate to have had a viable population of wood thrushes around here, these last several years. But maybe they’re dwindling and we’re hearing the last of them now? This year’s lone caller was unsettling. It’s just a matter of time before we will no longer be thrilled by their wonderful song.

I wonder if this year’s single thrush’s different song is because he’s not one of our local birds, but one who has moved in from someplace else. Birds develop regional accents in their calls—especially if they tend to hang around the same location. They learn the local dialect and stick with it. But if a juvenile doesn’t get exposed to its species’ normal song, it’ll develop its own distinctive—and very much simpler—song.

So this lone caller could be a lonely juvenile who did not have mentors around to teach him. Or he could be from another region, and has moved into our territory—either because his native habitat has disappeared, or even that climate warming has driven him a little north this year. (Maybe that’s a Georgia accent I’m hearing?)

We also had fewer Louisiana water thrushes calling out this year, and the calls we did hear were also a little different from the past. So I wonder if we may be experiencing the same thing with both kinds of thrushes: a decrease in population and a subsequent change in calls. I hope not.

When the number of birds declines in an area, the lesser-skilled or less aggressive males begin to predominate for a while. In a normal situation, the best singers prevail, causing the poorer singers to slink off and lose their chance to mate. In any given year, most of the birds who could mate, do not do so, because they get shoved to the margins. But as the population drops off, the less talented (and maybe less fit and healthy) birds get their chance. Maybe that’s what’s going on here?

I can only guess how lonely it must feel to a bird, as the population declines and they find mates increasingly scarce. At first, maybe the less fit birds would flourish, because they have a chance to claim territory they’d otherwise be pushed out of. But as time goes by and the population further decreases, even those who persevere can’t find mates. What’s it like, for those last few birds, as they search in vain? How does the last bird feel? Does he or she sense something wrong?

After a few weeks of the strange-calling wood thrush singing out with his truncated song, we no longer heard him at all. Did he fail to attract a mate? Did the local females reject his call as being just too foreign? Did he move on to yet newer territory, seeking better luck? Later, we heard a few hesitant wood thrush calls far off… too far off to discern which bird it might be.

I pray that this year was just a weird experience, and we may once again hear that old, thrilling call next spring. At some point, however, we (or our survivors) will hear the last thrush call. The termination of a natural phenomenon that’s continued for hundreds of thousands or even millions of years is very sad.

Wood Thrush Encounters

Listening to bird calls is an endlessly enjoyable game for me. Trying to identify some of the birds I hear has been a big challenge—which the purchase of a CD containing the calls of all American birds has only marginally helped. (Maybe the choices are just too many?)

Some birds call with melodious songs, while others seem to squawk with a nerve-jangling noise. I love ‘em all! The star of our bird singers is the wood thrush—the winner of the most-beautiful song category, hands down.

It took me awhile to identify the wood thrush from its call, as it is a very shy creature. It prefers dense woods and is a mottled brown-and-cream color, that effectively fades it into the background. We are fortunate to have several of these birds in our surrounding woods. They are the first singer in the early morning and the last to sign off at night. It is helpful that he often sings alone, because his song is quiet and exquisitely beautiful. One wants to listen fully when he calls.

The wood thrush song is extremely varied and complex, consisting of three parts, or movements. Part one begins very quietly—a soft, low “po po po,” that can be heard only if he’s very close. In fact, it’s more like a warm up and not a real call. Part two is a gurgling, flute-like movement, of 3-4 notes. Part three is a very high-pitched single note, sung in a rich, tremolo manner. The note is held for a moment and then allowed to fade.

The interesting part of his song is the second movement. It’s like a Bach invention—the same 3-4 notes are played each time in a different order and tempo, creating multiple variations on a theme. But part three also varies beautifully. It’s pretty much the same note each time, but is given fascinatingly varied buzzes, trills, and overtones.

The wood thrush assembles his complete song in endless variations. Sometimes one movement will be eliminated; sometimes it gets repeated twice, alone. I’ll find myself riveted by his performance, hoping he doesn’t stop, trying to guess what variation he’ll do next. What an incredible skill!

Of the many hundreds of times I’ve encountered the wood thrush song, I’ve seen the bird only twice. Once my spouse and I were hiking through the woods when two thrushes flew down to the ground in a clearing and played with each other for a couple of minutes. We stood as statues, stunned. The other “face-to-foot” encounter was completely bizarre. Walking slowly to my hermitage at dusk one night, I stepped on a wood thrush. Yes! Stepped on one! That’s about as likely as getting hit on the head with a meteorite. I thought I had crushed it, but it slowly and weakly hobbled off into the underbrush. I doubt that he had the wind to sing that evening.