Clark’s Nutcracker is one of the millions of mysteries that Nature has to throw at us. It is just a 5-ounce bird (and sometimes less) and if its brain is weighed, it turns out to be near zero. But, experts have found that this tiny bird has the incredible ability to memorize, on an average, 10,000 maps. The number of maps it memorizes ranges anywhere between 5,000 and 20,000. That’s one hell of a job and scientists are having real tough time figuring out how they manage to do so.
So, what’s all the fuss about Clark’s Nutcracker and Maps?
This tiny bird is known for collecting and hiding seeds since August every year till late November. By the time it is December, the bird embarks on finding those seeds and using them as food source.
In August, when it is high summer, whitebark pine trees produce the food for these little birds. These trees produce seeds that are neatly and tightly packed in their cones. That’s when the party time for these nutcrackers begin. They will shoot from tree to tree and look for the seeds. They will start harvesting the seeds by tearing open the cones using their very sharp beaks and pull out the seeds one by one. The birds will store the seeds in expandable pouchs that are present right under their tongues.
A few people conducted a study to figure out how fast the Clark’s Nutcracker can actually harvest. It turned out that they are pretty fast and end up collecting up to 32 seeds in a single minute. According to Russell Balda and Vander Wall, at one go, a Clark’s Nutcracker stores anywhere between 84 and 102 seeds in its pouch. According to Diana Tomback, a biologists, these birds store less seeds in their pouches in a single go, with an exception of one unusually large nutcracker she saw that carried 150 seeds.
So, what does the Clark’s Nutcracker do with these seeds?
Well, this bird caches them for the severe winter months when food supply is wiped out. Since August to November, the birds cache the seeds in different spots just like the squirrels and chipmunks do. Clark’s Nutcracker can hide the seeds it collects in a variety of places. They may tuck the seeds in nooks of tall trees or bore little holes on topsoil and bury the seeds. A single cache usually contains no more than two to three seeds. By end of November, a single nutcracker will have created anywhere between 5,000 and 20,000 caches of seeds. And, these caches are actually spread out in different locations.
December – Survival of the Clark’s Nutcracker depends on those caches!
So, when it is December, there’s no more food supply. All whitebark pines just stand bare and frozen. Survival requires food. This is when the Clark’s Nutcracker starts utilizing the hidden treasures. This is where things get really interesting. They remember all the hiding spots – up to 10,000 of those spots. The question is, “how do they find the seeds?”
According to experts, a nutcracker uses the following mechanism right for hiding the seeds:
- A nutcracker will first spot two to three objects that are permanently located in a spot. For instance, a rock or a tree or a bush. These objects are actually markers.
- From the hiding spot, these markers will be spread out in different angles.
- According to biologist Diana Tomback, during hiding the seeds, the birds will triangulate on a place of hiding with respect to the distance from the permanently located objects and memorize the photograph of the triangulation.
Alan Kamil – a psychologists has a slightly different view. According to him, instead of measuring the distances for triangulating on a hiding spot, the birds actually measure the angles of the landmarks from the hiding spot. So basically, they don’t do linear measurements but rather make use of geometry and angles.
It hardly matters whether Tomback or whether Alan is right. The thing is that, whatever mechanism the birds use for identifying a location of a hiding spot is incredible.
Now, when December makes a grand entry with snow, the birds will fly to spot where the seeds are hidden and sit on a low branch. According to Diana Tomback, they will look around a bit (i.e., they will look at the reference points or landmarks and finally land at a spot and start digging and then voila! They will find the seeds and happily eat or carry them to feed the chicks.
Back in the 70s, Vander Wall ran an experiment in which he simply moved the markers slightly to observer whether a Clark’s Nutcracker can still locate the seeds or not. Interestingly, the bird failed to located the seeds because it started digging at a different location. Wall’s experiment pretty much proves both Tomback’s and Kamil’s theories. The birds definitely make use of markers.
The big question – How does a Clark’s Nutcracker remember all those locations?
That’s an incredibly difficult question. Experts are not sure about that. They only assume that much like Chickadees (who are also known for hiding their food and later retrieving them), a Clark’s Nutcracker is capable of growing more brain connections (neurons) that allows it to remember incredibly large numbers of hiding spots. In case you don’t know, the Chickadees are known for growing bushier brains just when they need it and then their brains contract when they don’t need to remember too much. So, whatever method a Clark’s Nutcracker uses for finding the locations or maps, it does it extraordinarily well. During December, this bird will simply retrieve the snapshot of the location and markers and find the hidden treasure. How their brain works is still a mystery we need to crack.