On the evening before I would leave for my journey home, Christy and George hosted a potluck party. Shadows fell on the white frozen middle of the pingo as the western sky turned yellow and orange and the spruces became dark silhouettes. A pair of pintails again landed in the open water along the pond’s edge. The cranes were standing, each on one leg, their heads tucked into their back feathers. People crowded around the spotting scope in the living room, watching them occasionally shift position, lower a leg, poke a head out to look around. Suddenly the person then at the scope erupted with an exclamation: “They are mating!” She had seen the male approach the female with her spread wings, mount, flutter, and jump off. The pair had bowed to each other. Suddenly many people crowded around the scope to watch.
Why, I wondered, would anyone, or almost everyone, want to watch cranes mate? Why was nobody interested in watching the mating activity of the two ducks, or of the numerous redpolls? Could it be, I wondered, because we feel a closer kinship with cranes than with other birds?
Cranes are similar to us in many ways. Some are nearly as tall as a person. They walk on two long legs like us, albeit with a much more graceful and deliberate gait, so that they remind one of a caricature of a gentleman or an elegant woman on a leisurely stroll. The sandhill crane’s red bald pate and sharp yellow eye add to the caricature. Cranes form lifelong pairs and stay together as families, but they are also gregarious and join up into large groups. They form a strong attachment to their home. They not only make music with trumpeting calls that sound like bugles, but they also dance, and do so on various occasions.
All of the fourteen species of the world’s cranes dance. Crane dancing involves running, leaping into the air, flapping the wings, turning in circles, stiff-legged walking, bowing, stopping and starting, pirouetting, and even throwing sticks. Dancing is primarily done by pairs and presumably functions in cementing pair bonds and/or synchronizing reproduction. But it can also be induced at any time, and it stimulates other cranes to dance. Even the young colts perform some of the species’ dance. Possibly it serves as practice and could be motivated by the same basic emotions of joy that are an indicator of health important to mating.
Cranes’ dances often stimulate humans to dance as well and have been mimicked in many cultures all over the world where cranes live. Crane dances were performed by ancient Chinese, Japanese, southern African, and Siberian people. If not emulated, cranes are admired. In the Blackfoot tribe of Native Americans of northern Montana, the last name “Running Crane” is common.
Nerissa Russell, an anthropologist, and Kevin McGowan, an ornithologist from Cornell University, revealed that eighty-five hundred years ago at a Neolithic site in what is now Turkey, people probably performed crane dances using crane wings as props that were laced to the arms. Furthermore, someone of these people apparently hid a single crane wing in a narrow space in the wall of a mud-brick house along with other special objects (a cattle horn, goat horns, a dog head, and a stone mace head). Russell and McGowan also found evidence that vultures may have been hunted for their feathers for presumably a much different costume worn as well for a ceremonial purpose. The authors inferred that the cranes were linked with happiness, vitality, fertility, and renewal (since they arrived in the spring). While the crane dance was one of life and birth, and possibly marriage and rebirth, the vulture dance was associated with death and perhaps return to the afterlife.
Russell and McGowan believe that the crane wing interred in the wall of the house was never intended to be seen. It was a symbolic object related to marriage and construction of a new home and may have been coincident with a particular human marriage and home-making. The associations among dancing, pairing, and raising young and home would have been natural for people who saw cranes return to their home ground, just as I had seen Millie and Roy do. Seeing the close parallels in the biology of the birds with their own lives, and understanding the cranes’ dancing as helping to make or cause the good things that followed, Neolithic people would have been compelled to symbolically emulate the crane dance of homecoming and of new life.
Beelining
Observation sets the problem; experiment solves it, always presuming that it can be solved.
—Jean-Henri Fabre
CRANES FLY AN ENORMOUS DISTANCE TWICE ANNUALLY, BUT relative to their size, bees also fly huge distances—up to ten kilometers—and the foragers may perform such trips hourly. We can experiment with them to find out how they navigate. What we know about bee homing so far is nothing less than astounding, and it is built on a long history of research, primarily pioneered by the imaginative experiments dreamed up and performed by an Austrian named Karl von Frisch and his colleagues that date back over a half-century. Arguably, our knowledge dates back still further to early American frontiersmen trying to find bees’ treasure troves of honey.
In 1782, Hector St. John Crèvecoeur, a writer and farmer from Orange County in New York State, wrote:
After I have done sowing, by way of recreation, I prepare for a week’s jaunt in the woods, not to hunt either the deer or the bear, as my neighbors do, but to catch the more harmless bees. . . . I proceed to such woods as one at a distance from any settlements. I carefully examine whether they abound in large trees, if so, I make a small fire on some flat stones, in a convenient place; on the fire I put some wax; close by this fire, on another stove, I drop honey in distinct drops, which I surround with small quantities of vermillion, laid on the stones; and I retire carefully to watch whether any bees appear. If there are any in the neighborhood, I rest assured that the smell of burnt wax will unavoidably attract them; they will find the honey, for they are fond of preying on that which is not their own; and in their approach they will necessarily tinge themselves with some particles of vermillion, which will adhere long to their bodies. I next fix my compass, to find out their course—and, by the assistance of my watch, I observe how long those are returning which are marked with vermillion. Thus possessed of the course, and, in some measure the distance, which I can easily guess at, I follow the first, and seldom fail of coming to the tree where those republics are lodged. I then mark it [presumably with his name to claim ownership].
James Fenimore Cooper, author of the Leatherstocking Tales of the American frontier, of which The Last of the Mohicans is probably best known, in 1848 published the novel The Oak-Openings; or, The Bee-Hunter. Here Cooper depicts a different, perhaps more reliable method than Crèvecoeur’s of the frontier activity that came to be called “beelining.” Cooper’s story takes place during July 1812, in the “unpeopled forest of Michigan,” where, due to the Native Americans’ lighting periodic fires to clear the ground, there were many flowers among the scattered oaks. This was ideal honeybee habitat, and here the bee hunter Benjamin Boden, nicknamed “Ben Buzz,” practices his art. Ben captures a bee from a flower by placing a glass tumbler over it and sliding his hand underneath. He then places the tumbler with the captured bee on a stump next to a piece of filled honeycomb. He puts his hat over the tumbler and the honeycomb so the bee will not be able to escape. He waits as the bee, stumbling around in the dark, eventually finds the honey. Once it is preoccupied with imbibing the honey, it quits buzzing, and the silence is the signal for Ben to remove the hat and then the glass, as the bee will stay to finish its feast and will fly up, circle the honeycomb, and depart directly toward its nest. He then follows the bee to the tree, chops it down, and is rewarded with just over one hundred kilograms of honey. Easier said than done.
American honey hunters eventually added refinements to their beelining techniques. The main improvement was the invention and use of a “bee box,” a small wooden box designed to catch a bee and get it “drunk” on a hunk of honeycomb. It was used in Maine when I was a kid (I still own mine). George Harold Edgell, a lifelong bee tree hunter from New Hampshire, wrote in 1949 in a pamphlet titled The Bee Hunter that “one’s first task is to catch a bee and paint its tail blue” and “this must be done gently [because] bees do not l
ike to be painted. To paint a bee, it is best to wait until it is eagerly sucking up a thick sugar syrup and is too pre-occupied to notice.”
By 1901 Maurice Maeterlinck, the Belgian playwright and Nobel laureate in literature, described in The Life of the Bee his scientific experiments on bees that were individually identified with daubs of paint, from which he deduced that these insects could communicate their discoveries of food bonanzas to hive mates that would then navigate directly to the food. However, American woodsmen not only had used similar methods, but had also, through their beelining, already gleaned that same surprising insight into what the bees could do. Maeterlinck credited his American predecessors for their discoveries and wrote, “The possession of this faculty [to communicate food locations to hive mates that then can navigate to the food] is so well known to American bee hunters that they trade upon it when engaged in searching for nests.”
Although early American woodsmen, whose lives depended almost directly on the knowledge gained by close contact with nature, were beelining devotees who had deduced that honeybees recruit hive mates, it would remain for Karl von Frisch to unravel the marvelous story of how the bees communicate within the hive. He earned the Nobel Prize in Physiology or Medicine for this work. I feel lucky that a Maine neighbor, Floyd Adams, took me beelining when I was eleven years old, and that when I was a teenager, my father gave me an inspiring little book by von Frisch entitled Bees: Their Vision, Chemical Senses, and Language. It explained the experiments that he and colleagues had performed. They were mesmerizing because they connected the practical experience of beelining in the Maine woods with the imaginative power of a scientist who had penetrated into the core of the bees’ world, their hive, their home.
Floyd’s family’s home was the farm four hundred meters down our dirt road. It was populated by chickens, geese, cows, pigs, plus all the other usual and unusual wildlife that lives in a place with a tolerance for disorder. Along with Floyd, my companions were the four Adams boys, Butchy, Billy, Jimmy, and Robert, an in-law of theirs. Floyd, a dark-haired, mustachioed, wounded Marine Corps veteran recently returned from the Pacific, had a bad limp and a thirst for Black Label beer. Leona, his blond, petite wife, appreciated his fondness for honey but less so his taste for beer. He and the “boys,” after a hot day haying, sometimes went fishing on our nearby Pease Pond in the evening, but in August our big draw was always the beelining.
After we found a bee tree, we carved our initials into the bark to proclaim ownership (property lines were irrelevant with regard to bee trees; finders keepers was the rule), and at some convenient time we returned with crosscut saw, axes, wedges, a beehive, and pails and kettles for honey. Getting part of our living from the land was fun, and it meant understanding and using the bees’ homing behavior to find their hollow trees in the forest and resettling them into a new home, which we brought back to the farm and set up at a window in the attic of the house.
Fast-forward to a quarter-century later: My nephew Charlie Sewall and I are in a patch of goldenrod blooming in a pasture where each fall the wild honeybees gather nectar to top off their honey stores for the coming winter. We start by capturing a single bee in our bee box, a simple four-sided wooden box that has a ten-by-fifteen-centimeter piece of honeycomb with sugar syrup filling out the bottom. We dab the box with a drop of anise for scent and capture our bee by holding the box under her after she has landed on a flower and then slapping the box cover over her. At first the captive buzzes in the box trying to escape, but the buzzing stops when she stumbles onto the sugar syrup and starts to tank up, which will take her a minute or two. We then remove the cover and set the open box onto a pole that reaches to just above the tips of the goldenrod. We gently daub her with a spot of paint while she is absorbed in sucking up syrup, as I remembered Floyd doing. We then hunker down into the goldenrod and wait as she continues sucking up her newfound sweets that she will soon share with her hive mates. After about two minutes, her honey stomach is filled. She crawls out onto the edge of the box, stops to wipe her antennae with her front feet, lifts off, and flies back and forth downwind of the box. We duck lower to keep her silhouetted in sight against the sky as she starts flying loops, which become increasingly wider and oriented in one direction. Finally she straightens her flight path and takes off, making a “beeline” into the distance. Knowing that nobody in that direction keeps bees, it’s clear that she is on her way to a bee tree. She will soon be back with others, and we then consult our wristwatches to time her trip. A bee flies about four hundred meters a minute, and it may take her three to six minutes in the hive to regurgitate and unload her honey stomach’s contents into the mouths of begging, receiving bees.
We settle down and wait, and after perhaps ten minutes or less a bee suddenly appears and makes very rapid zigzagging flights just downwind of the box. The sound of her fight has a higher pitch than that of the bees foraging on the nearby goldenrod flowers. This means that she is more motivated and has a higher body temperature because of the rich food she is expecting. She settles into the box and starts imbibing the syrup. More bees will come soon, and when they get near our bee box, they will be guided in by the scent of the anise that marks the spot. After they tank up, we watch their flight directions.
If the food is in the immediate home vicinity, the bee does a “round dance” on the honeycomb when she returns to her home. She repeatedly runs in small circles while shaking her abdomen, and she regurgitates small samples of her find at intervals during her dance. If they become motivated after receiving information about the quality and scent of the food advertised, her hive mates leave the hive and search for the advertised food. If it is beyond a few hundred meters, the bee alters her dance to also contain information concerning location. The distance of the journey to the food is proportional to the duration of the waggle runs, and the angle of the straight runs with respect to the vertical direction informs the bees in what direction to fly when they leave the hive. If the straight run is in the up-direction on the honeycombs (which always hang vertically in the hive), the food source is in the direction toward the sun. If the food location is, for example, at an angle of ten degrees to the right of the vertical, the food direction is ten degrees to the right of the horizontal component of the sun direction when the bee would fly from the hive. Thus, her behavior is a symbolic representation in body movements of the flight to the food.
The first steps in the evolution of recruitment likely involved simple alerting signals in or at the nest entrance before takeoff. Other bees could have followed those signaling bees, probably by scent, for at least a short distance in flight. Through a few million years, the alerting likely became modified to take on an ever-greater leading function by bees flying in an ever more conspicuous manner in the direction of the food, so that followers could start off flying with ever greater accuracy in the right direction. These flights, later in the evolutionary progression, were eventually restricted to a buzz run directly on the top of the combs, but still in the food direction. We can infer this, because such “primitive” recruitment is still found in some tropical honeybee species that have their combs in the open air, where this mechanism makes sense. But open-air homes, though convenient for such communication of food location, were vulnerable to predators and also precluded the bees from living in huge areas of the globe, those with cold climates.
Homes in hollow trees allowed the bees to live in areas where they would otherwise be excluded because of cold and/or nest predators. But in such safer homes the combs hung from the roof of a cavity and left no horizontal dancing platform, and additionally the “dance floor” was now in darkness, so bees could not point directly toward the food. Even if they could, they would not be seen. But a breakthrough for indicating horizontal directions on vertical surfaces became possible after some bees started using the hanging flat surfaces of combs as their dancing platform while indicating the sun’s location as the up or “toward” direction in their dance. Additionally, tactile rather tha
n visual orientation became predominant for recruits in reading the code within the nest.
It is amazing enough for an animal to be able to navigate to a location it has never been to before. But some ants do something even more amazing. In North Africa, desert ants live in underground homes where they are protected from the heat. But they must venture out onto the searing surface periodically to forage by scavenging on heat-killed prey. The ants are fast runners that have evolved a very high tolerance for heat. Still, at times it is a matter of life and death even for them to make it back to their cool underground home; they cannot afford to wander on the sand surface for an extended time without access to their shelter to cool down and replenish body fluids. This is where their homing ability comes in; they may have zigzagged in all directions to find a heat-killed insect, but after finding one they must make a straight “ant line” directly back home. This begs the question, Since they are often on a featureless plain and have not kept a steady course, how do they know in what direction to head home?
If one captures bees in one pasture and releases them in another, they usually depart in the direction they would have flown from the original field. That is, they act as one would expect if they do not realize that they have been moved to a new location. Rüdiger Wehner and his colleagues at the University of Zurich came to the same conclusion about desert ant homing in their lifelong experimental studies. The ants use the sun as a compass, but a compass is not enough; the ants, when released from a point they had not themselves traveled to, like the bees caught in one pasture and released in another, apparently got lost.
For homing you must know where you are on “the map” before you head off in the correct direction. The desert ants can return home, but only if they walk to where they find themselves. Wehner concluded that the ants’ homing mechanism involves somehow calculating where they are at all times, probably in measuring distance by keeping a kind of count of their steps, and also keeping track of the angles of their direction from their home relative to the sun’s location. These were not mere speculations, but a hypothesis tested in painstaking experiments that entailed altering the ants’ perception of the sun (holding filters over them that varied the direction of polarized light that they, like bees, use in orientation) and altering their stride length (altering their leg length by gluing on extensions) to find out what information they valued and how they used it. Presumably bees could also have a similar “map sense,” and Randolf Menzel, a neurobiologist in Berlin, was trying to find out how it might work.
The Homing Instinct Page 3
