It’s been burying seeds since August. It’s hidden so many (one study says almost 100,000 seeds) in the forest, meadows, and tree nooks that it can now fly up, look down, and see little x’s marking those spots —here, here, not there, but here—and do this for maybe a couple of miles around. It will remember these x’s for the next nine months.
This is an assumption based on how humans make maps. Is the bird using an aerial map (that covers several square miles) that it has composed from “little maps” that are based on the arrangement of a few objects on the ground, in 5,000-20,000 separate locations? Does it then transform this complex projection (from ground points to an aerial view) into a “graphic map” with x’s on it? This is where BEING LITERAL counts, if one is to understand how the bird thinks; that is, how it collects and processes information from the environment, and then arranges it in a useable form. Does the bird rely on a built-in Google Map app?
Humans are not very good at “imagining” how other life forms function in relation to the environment. Are these maps at all, or simply images? In visual thinking, the image IS the content. Does the bird brain compare what it sees while searching for caches with an image that is embedded in its visual records (and is always available and “updated” as the environment changes) or is it calculating distance and location mathematically, using “trigonometry software” like a computer? Either way, it still needs an accurate “memory” of locations… which for the bird must be acquired through its senses – perhaps several senses are involved?
How does it do it? / 32 Seeds a Minute
It starts in high summer, when whitebark pine trees produce seeds in their cones—ripe for plucking. Nutcrackers dash from tree to tree, inspect, and, with their sharp beaks, tear into the cones, pulling seeds out one by one. They work fast. One study clocked a nutcracker harvesting “32 seeds per minute.”
These seeds are not for eating. They’re for hiding. Like a squirrel or chipmunk, the nutcracker clumps them into pouches located, in the bird’s case, under the tongue. It’s very expandable … The pouch “can hold an average of 92.7 plus or minus 8.9 seeds,” wrote Stephen Vander Wall and Russell Balda. (Aye, yai yai!) Biologist Diana Tomback thinks it’s less, but one time she saw a (bigger than usual) nutcracker haul 150 seeds in its mouth. “He was a champ,” she told me.
Next, they land. Sometimes they peck little holes in the topsoil or under the leaf litter. Sometimes they leave seeds in nooks high up on trees. Most deposits have two or three seeds, so that by the time November comes around, a single bird has created 5,000 to 20,000 hiding places. They don’t stop until it gets too cold. “They are cache-aholics,” says Tomback.
When December comes—like right around now—the trees go bare and it’s time to switch from hide to seek mode. Nobody knows exactly how the birds manage this, but the best guess is that when a nutcracker digs its hole, it will notice two or three permanent objects at the site: an irregular rock, a bush, a tree stump. The objects, or markers, will be at different angles from the hiding place. (???)
Next, they measure. (How are they measuring? Do they use feet and inches or the metric system? A tape measure? A laser scanner? LOL) This seed cache, they note, “is a certain distance from object one, a certain distance from object two, a certain distance from object three,” says Tomback. “What they’re doing is triangulating. They’re kind of taking a photograph with their minds (brain) to find these objects” using (3) reference points.
You can see from the video that “triangulation” is not what the researchers think it is!
Psychologist Alan Kamil has a different view. He thinks the birds note the landmarks and remember not so much the distances, but the angles—where one object is in relation to the others. (“The tree stump’s 80 degrees south of the rock.”) Aye, yai, yai! These nutcrackers are doing geometry more than measuring. (OMG!)
Yes, birds think in words; measure distances and angles, take notes, and identify “trees” as trees, “rocks” as rocks, and “do the math” (wrongly) just like psychologists. Another huge Asperger sigh…
Note that TWO points are needed for triangulation: point A and point B. This requires that the bird records data from two different positions in the landscape at a known distance from each other. But, even then, it’s not the “point” where a cache can be found that can be calculated, but the DISTANCE TO THE TREE (along dashed line) from the baseline. If the cache is in or below the tree, the bird can SEE where it is…
If we assume that (what the authors really mean) is that the marker objects exist at points A, B, and C, then why is there any need to “do the trig” or even make a map? The cache simply exists within the area defined by points A, B, C. On the ground these markers (an irregular rock, a bush, a tree stump) are not going to be more than a few inches to feet apart… a small area to search. And if the bird has an existing image of the area that includes the position of the buried seeds – easy, peasy!
Does the bird actually need an accurate map based on distances and angles to find seeds, when it has established an enormous number (5,000 – 20,000) caches, or will a few visual landmarks get it “close enough” to rediscover a sufficient percentage of them to provide for survival? Does it actually “find” each and every one of the 100,000 seeds? (I’d like to see proof!) What about the ones that other animals discover and eat? What about those displaced by rain, snow, wind, erosion, tree limbs or whole trees falling down; leaf litter is hardly a “permanent” material! What happens when one or more markers and the seed location are buried under snow? How is that explained?
To see what is involved in mapping go to: http://www.icsm.gov.au/mapping/surveying2.html
However they do it, when the snow falls and it’s time to eat, (they don’t eat during the rest of the year?) they’ll land at a site. “They will perch on a tree,” says Tomback, “on a low branch, [then light onto the ground, where] they pause, look around a bit, and they start digging, and in a few cases I’ll see them move slightly to the right or to the left and then come up again (??)”
She’s convinced that they’re remembering markers from summer or fall and using them to point to the X spot—and, “Lo and behold, these birds come up with their cracked seeds,” she says. “And it’s really pretty astounding.”
In the 1970s, Stephen Vander Wall ran a tricky little experiment. He shifted the markers at certain sites, so that instead of pointing to where the seeds actually were, they now pointed to where the seeds were not. OMG!
And the birds, as you’d expect if they were triangulating, went to the wrong place. Note that this “experiment” was not conducted in the wild, but in artificially constructed conditions controlled by the “researchers”… who don’t understand triangulation…
But at sites where he left the markers untouched, the birds got it right. That’s a clue that each of these birds has thousands of marker-specific snapshots in their heads that they use for months and months. When the spring comes and the birds have their babies, they continue to visit old sites to gather seeds until their chicks fledge. A “photographic” image (and images recorded by the brain) include the details needed for identification of what is within the frame of capture; the relationships between content details are “fixed” in the pattern. The bird does not need to “abstract” markers from the environment; everything is included in the image.
The mystery here, the deep mystery, is how do they manage to store so much data in their heads? I couldn’t possibly do what they do (I can’t even remember all ten digits in a phone number, so I’d be one very dead nutcracker in no time). Is their brain organized in some unique way? (!!!!!)
Neurotypicals are perpetually amazed that other living things, which have been produced by the rigors of evolutionary selection over millions of years, could possibly possess functions and skills beyond those of an infantile domesticated social human.
Is their brain plastic? Can it grow more neurons or more connections when it needs to? Chickadees are also food hiders, and they do grow bushier brains when they need to, expanding in the “remember this” season and contracting afterward. Do Clark’s nutcrackers do that? We don’t know.
Whatever it is they do, I want what they’ve got.