Wednesday, June 08, 2016

CSI: My Front Yard

Sunday night I returned home to find a big 'ol divot in our front yard. What the heck, right? Our lawn guy has been working his magic and through absolutely no contribution from me, things are looking solid. Who, or what did this, and why? Let's follow the evidence!

Step one, collect some crime scene photos:

I see half a nut on the sidewalk, and the rest of the nut in the ground.

Although it seems awfully cliche, I think this evidence points to squirrel activity. From this page on the topic we learn:

The most common way squirrels store their food is by burying it in scattered caches around their territory to dig up later when food is scarce, such as in winter. This way is usually favorable because it makes it harder for other animals or squirrels to pilfer their reserves as it's scattered in many different locations.

That explains why we'd find the remains of a single nut. Though it isn't winter, so perhaps my thinking is all off. But for the sake of argument, let's assume it isn't.

The crime probably went down like so: at some previous time, the squirrel buries said nut. Then while we're out of town, he digs it up, cracks it open, and leaves part of in the hold and nibbles on the rest of it nearby.

But this begs the question: how did the squirrel know where to find this buried nut? The terrain, thanks again to my lawn guy and not me, was pretty dramatically different. Furthermore, this is a surprisingly accurate hole, with no sign of digging nearby. This was obviously done by a pro.

Apparently it was once thought that squirrels used a sort of brute force method for dealing with food caches: bury a whole heck of a lot of them, and then use smell to find them, or another squirrel's cache's in the area. It was sort of like squirrel socialism:

"Squirrels have been criticized for hiding nuts in various places for future use and then forgetting the places. Well, squirrels do not bother with minor details like that. They have other things on their mind, such as hiding more nuts where they can't find them," wrote cheeky W. Cuppy in his 1949 volume "How To Attract A Wombat," 40 years before Lucia F. Jacobs and Emily R. Liman conducted the study that would un-sully the reputation of grey squirrels.

More recent thinking definitely puts squirrels in a more capitalistic mindset:

"Whether grey squirrels remember where they have buried their nuts has long been debated," Jacobs and Liman write. But with their experiment, which involved eight grey squirrels, each given 10 hazelnuts, they observed that squirrels are not as forgetful as people have traditionally thought.

The squirrels were each released alone in an outdoor area and allowed to bury their hazelnuts. The researchers recorded the hiding places each squirrel chose. Then, after two, four and even 12 days, the squirrels returned to the area. Even though the hazelnuts of each respective squirrel were buried close to each other, the squirrels "retrieved significantly more nuts from their own sites than from sites used by other squirrels."

In other words, the squirrel who dug up my lawn was most likely on a mission. He (again, or she!) was probably after that specific cache, and thanks to both memory and scent, was able to cleanly retrieve the nut with a high degree of accuracy. Read the entire study to find out more fascinating facts about squirrel behavior.

Watching this scattered cache food storage methodology play out literally in my front yard is actually pretty sweet. It's so easy to forget that squirrels and the rest of the critters in my backyard are on a daily mission to survive, and that means having food even in the dead of winter. Now about that divot in the front yard, where's my lawn guy's number...

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