Bounty From Above

The season is turning, and red squirrels are obsessed with gathering food stores for the winter. They will rely primarily on the cones of spruce, fir, and pine–and to a lesser extent on larch, eastern hemlock, and white cedar–for survival over the coming months. The squirrels’ preparations for the lean times ahead leave plenty of evidence. In the photo below the ground is littered with red pine cones. A few brown cones that fell the previous year contrast with the green of this year’s crop. When stored in a humid environment the tightly closed green cones will last through the winter without opening, preserving their precious seeds until a red squirrel pulls them apart to get at the nutritious nuggets inside.

The next photo was taken in a stand of Norway spruce, a tree that is native to northern Europe but was widely used in reforestation projects in the US during the twentieth century. Some of the trees in these plantations are large and produce copious crops of cones. The cones’ large size–some as long as eight inches–means they are a bonanza of food for red squirrels.

You can see another harvest in the photo below, this time the cones of white pine. Again, it’s the largest trees, the ones that tower over the rest of the forest, that produce the best crops of cones and attract red squirrels to harvest them.

These arrays of fallen cones don’t usually last long. After working in the tree tops to drop a supply of cones the squirrel descends and transports the bounty to an underground storage space, known as a larder. A red squirrel typically has a number of larders, often made by enlarging the natural spaces that form around large roots. Rock crevices and hollow trees may also be used, and cones are sometimes stored under fallen trees or even in abandoned buildings. Green cones stay tightly closed all winter and well into spring in these humid spaces.

The white pine cones shown in the next image were also nipped by a red squirrel, and these cones probably look more like the ones you’re used to seeing. There must have been an interruption before they could be transported to a storage cavity, because they’ve dried out and released their seeds. Our weather has been dry lately, so drying may have happened unusually quickly, making the cones useless for winter food. So if the seeds were released when the cones opened, where are they, you ask? Such a concentrated serving of edibles wouldn’t have gone unnoticed by birds and small mammals and would have been rapidly consumed.

I was curious about how the squirrels detach cones from branches. I imagined a a lot of yanking and chewing, which should have left tooth or claw indentations somewhere around the sides of the cones. But when I looked for marks, all I could find were small bits of exposed wood at the attachment sites. The photo below shows the lighter separation areas at the bases of some of the red pine cones I examined. On Norway spruce and white pine cones it was the same– all I saw were small separation wounds at the bases.

I realized I needed to see how cones are attached to twigs, and what I found suggests that nipping cones is pretty straightforward. In the next photo you see a red pine cone attached tightly to a twig. A squirrel need only bite through the attachment point by inserting its tiny incisors into the angle between the cone and the twig. This would produce a lighter colored spot at the separation point like the ones I observed on the dropped cones.

I’ve never seen this happening (how I would love to levitate to the top of a tree and watch!) but I did find a video of a red squirrel harvesting cones from a western pine, probably a ponderosa pine. You can see it here. (The clearest view starts at 2 minutes and lasts about a minute.) The squirrel perches on the branch and works from the back side of the cone, occasionally using its front feet but mostly just gnawing at the connection between the cone and the branch until the cone falls.

Finding the evidence left by these frenetic little creatures isn’t hard–just pay attention to what’s on the ground whenever you pass under conifers. You’re most likely to find signs of harvesting where there are middens (piles of discarded cone scales and cores) from previous years, since resident squirrels tend to keep the same territories year after year. And sound may guide you to a harvesting site. A falling cone lands with a thump; the bigger the cone the louder the thump. If a falling cone hits branches on the way down you’ll hear some plunks and bonks followed by a thump. Follow your ears toward the sounds and you’ll probably find nipped cones scattered on the ground and a red squirrel chattering angrily at you from high in the tree.