EPTThe squirrels behind my house are the most spoiled animals in existence. This all began when I was shopping around at the hardware store and a 90 dollar bird feeder caught my eye; I decided I needed it. 90 dollars is pretty expensive for an impulse buy for me but I'm frequently out on my back porch and I like seeing the occasional bird when I'm out there. I hoped this would draw more of them to the area.
It caught the birds' attention at first. I assume this isn't the first bird feeder they had seen, some of my neighbors in the area probably have them too, but they seemed to have a hard time getting at the food inside. Some of the anti-squirrel technology implemented into the bird feeder was making the means to food more complicated than the birds felt was worth their while. In the end, the birds gave up on the device and I still had two giant bags of bird seed left over.
Rather than let the bird seed go to waste, I decided to see if I could at least attract their attention by putting small piles of it on easy to reach posts in my back yard. They loved this. In two days my back yard was full of several species of birds; cardinals, woodpeckers, blue jays, doves, and finches. After watching them for a while I started to notice that each species of bird seemed to have it's own personality.
Bright red male cardinals would fight and chase each other if there was a female around. Woodpeckers were independent and were the only species other birds wouldn't mess with; would you mess with someone who could smack their face into a tree a hundred times a minute? Blue jays and doves were the bullies, they would chase smaller birds out of the yard. The doves were particularly aggressive and would gang up in groups of 4-5 to chase away the others. Finches are cute and fast. They would choose a safe spot somewhere far enough off, swoop in, grab 1 seed, retreat back to safety to eat, and repeat.
Anyway, having abandoned my 90 dollar bird feeder entirely in lieu of setting free food for all out in the open I was starting to attract more than just birds. The squirrels were especially enthusiastic about the hand outs. It started with just one, then two, then in a few days there were six regulars that I could count. Most people do not like squirrels in their yard. They steal birdseed, they will eat all the food in your garden if you have one, and they will throw their nuts and seeds in your air conditioning unit in some misguided attempt to store food. After watching the squirrels carefully however, I was starting to really like them. They didn't scare away any birds and their behaviors were surprisingly complex and fun to watch.
I noticed very quickly that, unlike the birds, the squirrels would not just eat their fill and then leave. The squirrels would eat their fill, then start stuffing their cheeks with seeds, then when their cheeks were full they would run to some seemingly random location, bury the seeds, and return to my yard for more. Repeat until birdseed is gone. I followed several squirrels many times on their journeys to stash their seeds and noticed that they rarely put food in the same stash spot. This struck me as curious: How does a squirrel keep track of all their stashes? What is the method? Do they use trail marks? It didn't seem the case. Rote memorization? I doubt it, they had a lot of spots, more than I could easily keep track of. Or is it an algorithm? More on this later.
Another curious behavior emerged: After only a few days of leaving the birdseed out in the open, I was noticing squirrels that would look through the windows of my house and keep track of my location at all times. I'd just be sitting in my office, look outside, and there's a squirrel on the fence glaring at me. I'd move to the kitchen, and the same squirrel would have moved to a tree outside the kitchen window, again, staring at me.
The squirrels were getting attached to me, as evidenced by them following my movements around the house, and I was getting attached to them. I decided I wanted to buy them a special treat. I went to the grocery store looking for squirrel food and decided on a giant bag of unsalted, roasted, peanuts. These will be great I thought. Much larger than the sunflower seeds I had been giving them and perfect for stashing. Plus, I figured, maybe if the squirrels like these more they will stop eating the birdseed all together and leave it for the birds. I woke up the morning after, walked to the kitchen (as usual squirrels staring at me through the window), walked outside to put out the usual bird seed, went inside, then took out the peanuts I bought and scattered them on the ground. I made it my mission this morning to gain more insight into how a squirrel chooses and finds it's stashes.
I am not a biologist. Everything I say is pure, casual, speculation. In all likely hood, nothing I say is true.
Squirrels use a simple algorithm for locating and deciding on stash locations.
It is a system I am going to describe as: Spot Points, Trails, Wall Points, and Jumps.
A Spot Point is a precise location where food can be found easily (I.E. my back yard).
A Trail is a path that leads between Spot Points and/or Wall Points. A Trail will either begin at a Spot Point and end at a Wall Point, or begin at a Wall Point and end at another Wall Point. A trail contains the variables Stealth and Energy Expenditure.
Stealth refers to how stealthy a squirrel can be while traveling along a Trail. This variable is desired to be as high as possible in order to avoid predators.
Energy Expenditure refers to how much energy must be expended in order to travel along a Trail. This variable is desired to be as low as possible in order to conserve valuable energy.
A Trail starts at a Spot Point or Wall Point and continues along the precise path where Stealth is highest and Energy Expenditure is lowest. A mathematical balance between the two variables must be reached.
If when following a Trail the Stealth and Energy Expenditure variables fall below a certain threshold, I.E. there is too little Stealth and/or too much Energy Expenditure, a Wall Point is encountered.
When a Wall Point is encountered, the surroundings are briefly surveyed to obtain a heuristic estimate of where the next best Trail will start. The Jump is then executed and the squirrel begins on the new Trail, again abiding by highest Stealth and lowest Energy Expenditure.
Squirrels ALWAYS stash their food at a Wall Point, I.E. in between two Trails.
It is desirable for the squirrel to limit the amount of Jumps performed, as a Jump requires significant Energy Expenditure.
A crude diagram:
![[image loading]](http://i.imgur.com/paYGxgr.png)
This system is useful because by simply keeping track of locations where food is easily located (Spot Points), all food stashes can easily be found by following the rules for Trails, since Trails abide by where Stealth is the highest and Energy Expenditure is the lowest every time.
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If this theory is correct, then by modifying a Trail a squirrel is using between Wall Points, I should be able to throw them off their stashes. I will be testing this theory in some indeterminate period of time to come.
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Questions for TL:
Does the "squirrel search algorithm" make sense?
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edit: Now with video!
Squirrel starts checking out the camera about 1:30
Worst case scenario is I'll start seeing more sunflowers in my back yard. 
