Following a fitful night’s sleep, I am off to a later start than I had hoped, but it is still early by any diurnal standards, and the cool morning air is slowly heightening my senses and broadening my smile as, alone, I walk down the trail.
Stopping at the upper dam I look south across the beaver pond, train my binoculars through a gap in the flooded forest. There is barely enough light to pick out several shadowy mallards milling into and back out of view. Closer by, resting comfortably in a little shoreline pocket behind a flooded hemlock, the resident drake hears my approach, swims from behind the tree, looks my way, then scuttles back to his mateI have arrived in this place where water caresses and chokes the forest’s feet, and trees drunk on their own tannins, stand forever sleeping, just in time for the last mysterious minutes before night slips finally away, and the owls take their curtain call. In this moment, more can be learned from sound than sight, and I lower my binoculars to listen to the dawn.
A careful duck who might float by undetected in the crepuscular dim, is immediately exposed when it flies. Unlike an owl’s softly serrated flight feathers, ducks are hard-edged. So when deep in the forested pond the milling ducks take to the air, the din is heard far and wide. Tuning into their broadcast, I hear them winging west, maybe to the bay, or perhaps to circle north to the little delta where scores of mallards will gather this morning along with mergansers, goldeneyes, and wigeons.
It is early for them to be leaving the pond, I think, and I wonder what triggered their sudden flight. The whoosh of wings only explains a certain 𝑤ℎ𝑎𝑡. 𝑊ℎ𝑦, remains a riddle. A bald eagle—a primary duck predator in these parts—would not be hunting them at this hour, but coyote could be about, or lynx, or wolf. I am too far away to be the cause of their unnerving, so something else must be out there.
Less than a minute after their departure, I hear a possible clue. A loud smack on the water rings out danger. Something has given a beaver cause for alarm, maybe the same thing that scattered the waterfowl. I scan what I can see of the pond, but everything is still, and the morning quickly slips back into quietude.
Ducks like the little potholes and beaver ponds that dot the forest and muskeg. Here, they blend into the edges or slip beneath a low canopy to hide from so many who would relish a tender breast for supper. But camouflage is not enough when you are one of the most delicious members of the ecosystem. Ducks must remain wary, and one key to staying en garde is flock teamwork.
Ducks, geese, cranes, and swans are all legendary for working together on long flights. Spring and fall, from Argentina to Alaska, people excitedly look to the sky at wave after wave of stringing echelons winging their way to winter or summer grounds. These vee formations allow each bird to use the updraft from the bird before it, giving all but the very front flyer an extra lift. Occasionally they switch positions, allowing the leader to take a break. But teamwork doesn’t end when migration does. Ducks also work together when they are potentially at their most vulnerable—when they are sleeping.According to a study published in1999 in the scientific journal Nature, ducks are able to “control sleep and wakefulness simultaneously in different regions of the brain.” In other words, ducks can choose to sleep half their brain at a time, rendering them both asleep, and awake—sort of like a Schrödinger’s Cat, but without the potential of the box being opened, and sleep being rendered permanent.
When a flock of ducks climbs onto a log and tucks their heads underwing for an afternoon nap, there will always be two individuals whose heads remain untucked. The two ducks bookending the row will each keep one eye opened. The eye that is closed, controlled by the sleeping portion of the duck’s brain, will face the other ducks. The open eye, controlled by the wakeful part of the brain, will face away, keeping a lookout for predators, protecting the whole.In the same way that in a migrating skein, ducks will occasionally change positions to rest the leader, sleeping ducks will wake up and move to the end of the row, take over the vigil, and allow the previous guard, now safely between two other ducks, to rest more fully.
All this thought about sleeping ducks is beginning to weigh on my eyelids, so when the quiet is broken by a red-breasted sapsucker chiseling a nearby snag, I take the call as my cue to move on.
While I was lost in thought, the resident pair of ducks moved from the shadows, and are now dabbling in the open. The drake keeps a close eye on me as I walk around the pond towards the muskeg and the ocean beyond.
Humpback whales are arriving daily now, ending their 3,000 mile swim from Hawaii and other tropical wintering grounds, and I don’t miss many opportunities to spend time looking for them. I plan to find a nice rock or log where I will sit and watch for spouts, but when I break from the trees, I find a stiff wind chopping the Inside Passage into a sea of whitecaps—tough conditions for spout spotting.
Staring out towards the distant Chilkat Mountains, I think about the giant whales making their long swim, having not eaten for months, eager to get back to seemingly endless schools of herring and hooligan. How tiring that swim must be, especially for newly born calves who are surviving solely off mother’s milk, and as vulnerable to orcas as ducklings are to bald eagles.
Migrating whale calves, who have developed neither the strength nor stamina of their mother, have been known to use a strategy similar to that of migrating ducks. Not surprisingly called echelon swimming, a tired calf will stay close behind its mother where it is pulled along inside her slipstream—a water vacuum formed in the wake of the whale, much like the draft of a race car being used by a teammate to save gas in long contests.
And the similarity between ducks and whales does not end there. Unlike a duck—or you and me for that matter—whales do not breath involuntarily. Every breath is a conscious act. Were it not, a whale calf would likely drown the first time it falls asleep. On the flip side, if they didn’t breathe automatically, sleeping would lead to suffocation. In fact, newborn whale calves have been known to die never having taken their first breath after not making it to the surface quickly enough.
By now, I suspect you have probably guessed where this is going. Whales, like ducks, sleep unihemispherically. This allows them to be aware of their surroundings, and take occasional shallow breaths with one side of the brain, while the other side is fast asleep.
My mind is swimming with these curious similarities. As I stare at the waves, I wonder how two seemingly disparate species could have such remarkably similar survival strategies. After a few thoughtful minutes of being fooled by whitecaps, I turn back into the forest and continue my slow loop.
Pausing at the dam, I wonder again what might have triggered the ducks, and alarmed the beaver this morning. Could I ask the beaver, I surely would, but there are none to be seen, and I doubt they would answer with anything other than another tail slap anyway.
I am also still pondering that larger question: How is it that two animals as different as mallard and humpback evolved the same strategy for sleeping? Using updraft and wake vacuum to conserve energy on long migrations are techniques easily explained as learned and taught behaviors, but not unihemispheric sleep. You can’t teach that, so we have to look at evolution.
In Darwin’s hummingbirds, natural selection is neat, tidy, and predictable. Feeding ecology predicts sexual dimorphic beak shapes. Case closed. Sometimes natural selection and adaptation works that way. Of course the adaptations themselves, though we call them strategies, are not choices, but random luck of the draw. Sometimes a random strategy leads to success and that strategy is passed on. Other times, a given strategy leads to extinction.
Clearly, whale and duck inherited the same sleep strategy, and it served them well, but where did it come from? Who was the ancestor for each of these species that evolved this ability, found success, and passed it on?
Humpback and mallard are species whose divergence is so ancient, you have to go back 300-360 million years to the carboniferous period and the appearance of the first amniotic egg to find a common ancestor. I don’t see how that trait could have come from there, so somewhere since that time, each of these species found this sleep strategy independent of one another. And the story does not end there.
It turns out that whale and duck are not the only animals who possess this interesting ability to rest half their brain at a time. A study conducted by researchers at Brown University and the Georgia Institute of Technology shows that a vestigial remnant of unihemispheric sleep remains in humans, too.
Ever sleep in a new bed and have a fitful first night’s sleep, then settle in for a good rest the second night? In that first night in a foreign environment, the left side of your brain does not sleep as deeply as the right, and is easily awakened by the smallest disturbance that might not phase the right hemisphere. As you grow accustomed to the new environment—sometimes in the very next night—sleep goes back to normal, and that small disturbance goes largely unnoticed.
So where does this come from? We already determined that whales and ducks acquired their strategies independent of one another, so who’s to say this strategy didn’t emerge several different times in the evolutionary tree? Our vestige is probably not connected to whale or duck at all.
In South America, harpy eagles pluck monkeys from the trees. In India, tigers have been known to kill and eat humans, as have black bears in North America. It seems to me that apes have long had plenty reason for keeping one eye open while sleeping, even if most of us nowadays sleep behind protective walls with little danger.
Whatever the case, from wherever it comes, at some point in our not too distant evolutionary past, our ancestors were unihemispheric sleepers, resting one half of the brain at a time, keeping the other side awake.
Quite likely, you and I never would have been born had the brains of our ancestors not shared a trait with both whales and birds, and we still possess a remnant of that common trait. In other words, every one of us inherited a little bit of birdbrain.
Back at the dam, a kingfisher plunges into the water, then flies to a limb and offers his waiting mate a meal. Nearby, a pair of sapsuckers take turns excavating a new nesting cavity ten feet below last year’s refuge. In the shadow of a stand of trees in the middle of the pond, a mallard drake lowers his head to the water and swims by his mate, who repeats the gesture in what is often a post-copulatory gesture.
My dictionary defines birdbrain as “an annoyingly stupid and shallow person,” but that is not evidenced by what I see in these pairs who all around me are working together in so many ways. They court, mate, feed, groom, protect, defend, and in many cases even sing to one another—yet another custom shared by whales.
These are not the acts of the “stupid or shallow.” I would say they are, in fact, just the opposite. It is certainly neither stupid nor shallow to look out for your sleeping brothers and sisters, or to take a turn flying in the lead so others may take a rest.
Stupid and shallow would be to ignore the vulnerable, leaving them open to those who would prey on them. Stupid and shallow would be to leave others to do all the heavy lifting without relief. Stupid and shallow would be to put the self ahead of the whole. These are not traits I observe in birds, nor are they the attributes of whales. I will leave it to the reader to consider what species possess these behaviors and in what measure.
And I henceforth wholly reject the accepted definition of birdbrain, and suggest we find a better definition for the word, something that more closely reflects the nature of our avian cousins. Perhaps something like this:
birdbrain | ˈbərdˌbrān | noun informal
a person who exhibits behavior in keeping with the caring, selfless, cooperative nature of birds
It should be considered birdbrained to take care of your fellowman. It should be considered birdbrained to tend to your children. It should be considered birdbrained to feed your love as courtship, to share in the burdens of homemaking. It should be considered birdbrained to give lift to those whose wings are weary, to watch over those who are sleeping, and to sound the alarm when others are in danger. It should be considered birdbrained to sing love songs.
These are the ways of birds, and these would define an epithet deserving of birds, one we all might aspire to being more deserving of, and perhaps something to be thinking about especially in this time of walking alone.
I am feeling my lack of sleep as I walk back to the truck. I need rest. I am also feeling my aloneness. Watching all these feathered friends taking care of each other can have that effect on one who walks alone.
When I get home, I will probably have a late breakfast, then crawl into bed for a nap. I am fortunate, and thankful to have a safe place to sleep in a comfortable bed surrounded by four walls and covered by a roof, but somehow that seems a poor substitute for chiseling a cavity with someone or having them on the other end of the log, with one eye open, keeping watch.
But napping alone does not—will not—preclude me from looking for ways to care for my brothers and sisters, for trying to as birdbrained as I am able. Perhaps that is the very least we can do for each other, just as the whales and and birds, by their example, teach us.
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What a wonderful and inspirational article. I will think of it often as I endeavor to be more birdbrained.