Well, rather than some rather far-fetched, silly, or vaguely plausible explanations of what the squirrels are doing in the local trees (that I reported on yesterday), I can now tell you what they are doing!
We have squirrel samurai! Or Samara Samurai. I stood and watched a squirrel just now with that wonderful technology that makes it possible for us older observers to hold our binoculars steady (if you are older and use binoculars regularly you really should look into Canon’s image stabilizing optics, they are world changing for birding). And I could plainly see what they were doing. A squirrel would reach out, nip off a small branch-let, fold the leaves together between its paws, and then with great relish and speed eat the samara!
And what, you might wonder, is a samara? It is the fruit of the cedar elm. Most elms flower and go to seed in the springtime, as do most other plants. But the cedar elm (Ulmus crassifolia) flowers in July and the fruit, or samara, form right now, in late September or early October. I can’t improve on this description of what the fruit looks like:
The samara looks much like a tiny green round ravioli, or those dots of explosive caps for toy guns of the past.
There are lots of these samara in the trees, but none on the ground where the squirrels have been feeding because they have eaten them all off and then discarded the branch-lets to build up in piles in our driveway and on the cars.
There is something very satisfying about answering your own question, but it is even more satisfying when you find out that other people have not figured out the right answer. On the 21st of October 2010, the Dallas Morning News published a column about this same behavior, but the Morning News organics columnist thought the squirrels were eating the cambium layer under the bark. Which makes no sense if you watch what they are doing. They even asked Dr. Jim Cathey, a wildlife specialist with Texas AgriLife Extension Service in College Station, who agreed “the cedar elm fixation is a puzzle if, indeed, it is a new behavior.” He suggests some possibilities including that the squirrels may be after a fungus growing under the bark. But no one seems to have gone out and just watched the squirrels. I can’t speak for why squirrels may trim twigs off other trees, if indeed they do. But as far as cedar elms go, it seems quite clear what they are doing.
When I was young my mother would urge me to investigate things by saying “Cease the moment of excited curiosity.” And I often did. Strangely, I never thought to look up who first gave that challenge to self-education until now. It was originally said by William Wirt (1772 – 1834) who was the Attorney General under James Monroe. And then, because of the astonishingly fulsome nature of Wikipedia, I found out a much more interesting story. Wirt argued before the Supreme Court in 1830 that the Cherokee nation was a foreign nation, and therefore was not subject to the laws of the state of Georgia. He eventually won the case and the Supreme Court declared that the Cherokee nation was “a distinct community, occupying its own territory, with boundaries accurately described, in which the laws of Georgia can have no force, and which the citizens of Georgia have no right to enter but with the assent of the Cherokees themselves or in conformity with treaties and with the acts of Congress”. We didn’t live out that Supreme Court decision too well, did we.
So, from samurai squirrels to the sovereignty of the Cherokee nation. Only on the internet!