I’ve been learning about nuts. Acorns, to be specific. From oak trees. Because they’re lying all around in great masses this year, much more so than usual. The “mast”, as the crop is called, is good. And by extension, I’m learning more about chipmunks, who eat the mast. The chipmunks are running around in great masses eating the great mast this year. Might be a connection.
I confess to being rather stupid about trees, a failing I keep meaning to correct. But this year’s bounty of nuttiness strengthened my resolve, so I picked up some books. (Stan Tekiela's invaluable little Trees of Pennsylvania Field Guide helped me identify our oaks.)
One in particular has been not only greatly informative, but also vastly amusing. I recently acquired this delight at our library’s semi-annual book sale. A great bargain at a dollar. Published in 1929 (mine is the original version, and still in its dust jacket), Tree Crops: A Permanent Agriculture by J. Russell Smith, is apparently still the classic work on the subject. The poet-farmer-writer Wendell Berry wrote in the foreword of the 1950 reprinting, “This book contributed to a fundamental rethinking of agriculture in our century.” No wonder Wendell Berry loved it. Besides the common sense and prescient thought that “farming should fit the land,” and despite the ponderous nature of the book’s title, J. Russell Smith has me laughing with every wry twist of phrase. Consider the 1st sentence in the chapter, “The Oak as a Forage Crop”: “The oak tree should sue poets for damages.” There’s also a picture of some sorry-looking muffins for the next chapter, “The Acorns as Human Food.” The caption reads, “Muffins made of Missouri acorns. Said to be good.”
Anyway, back to chipmunks. I had gathered up a bunch of different acorns, some from the Chestnut Oak (Quercus prinus, a white oak type), which at an inch or more in length are fairly big, and some much tinier ones from the Blackjack Oak (aka Scrub Oak, Q. marilandica, a red oak type apparently at the edge of its hardiness zone here in northeastern PA), and dumped them in a pile on a rock in the garden. The next morning, I noticed all the little acorns had disappeared, and all the big ones scorned. Clearly a preference had been established.
Graham said, “Hey, get more of those nuts, set up the camera, and photograph the chipmunk taking them.” He handed me the long remote camera shutter cord, and then we sat in wait from inside the house, ready to snap. Two hours elapsed before the chipmunks A) decided it was safe to come out of hiding and, after running around sort of aimlessly in the garden, B) finally re-found the pile of nuts. If it hadn’t been morning, all the waiting and peeping out the window would have been much more enjoyable with a glass of wine. (I clearly have standards that need some eroding.) Two different chipmunks availed themselves, first actually eating a nut or two, then stuffing the rest in their cheeks and running off, coming back and repeating the process of eating and stuffing.I discovered in Tannin and Lipid Content of Acorns in Scatterhoards and Larderhoards (Marianna Wood, Northeastern Naturalist, 12:4, 2005) that “…Tamias striatus (eastern chipmunks) …prefer acorns from white oaks for immediate consumption in the fall, but prefer acorns from red oaks for caching for winter use. In the fall, red oak acorns contain higher levels of lipids and tannins [making them more bitter] than white oak acorns [i.e., sweeter in taste]. ...Throughout the study, red oak acorns had lipid levels five to ten times greater than those of white oak acorns and tannin levels two to four times greater than those of white oak acorns.”
But as my little pile of bitter red oak type acorns disappeared, it was clear that our chipmunks, at least, will eat the tannin-rich nuts right away as well as store them, and ignore the supposedly sweeter white oak type completely. Maybe it’s a size thing.
By the way, I cracked open one of those big, supposedly sweeter Chestnut Oak acorns to see for myself. Didn’t do what J. Russell Smith recommended to remove the tannins. Tasted horrible. Spat it out. Drank some wine. Not making muffins anytime soon.