Deer Desperadoes

I wrote last year (“Masting Aftermath,” 12/26/12) about experiencing a heavy masting year for oak acorns. (The masting process is one in which oak trees somehow collaborate to grow a superabundance of acorns every few years, thereby coating the forest floor with far too many acorns for critters to eat—ensuring that some survive to grow the next generation's oak trees.) Everywhere I trekked in the woods last year, the ground was carpeted with countless acorns. I had to watch my step, lest I slip on them and fall.

So last winter the deer, squirrels, turkeys, and other critters were fat and happy—gorging themselves on the oaks' bounty. All that overindulgence came to a screeching halt this fall, as the trees were unusually stingy in their acorn crop. The result is severe hunger in the ranks of these acorn harvesters. I don't know how the squirrels and turkeys are faring, but we've seen lots of evidence of famished deer.

We depend on our free-roaming dogs to keep the deer from invading our garden, and they do a good job of it. A garden fence deters the deer to some degree, but the dogs love to chase any deer who takes a second look at the fence and is contemplating a jump over it into veggie heaven. So once again we made it through the summer with no deer incursions in the garden.

This fall has been a very different story, however. As foraging on tender plants in the woods was brought to a close by the beginning of cold weather and no backup supply of acorns was to be had this year, the deer have repeatedly invaded the clearing. Numerous shrubs and bushes do not get fenced, as the garden does. That is usually no problem, because I've chosen varieties of shrubs known to be shunned by deer.

Well, that may be true for normal years, but when starvation threatens, the deer become desperate. They'll eat most anything green, as well as many other types of barely edible plants. It's irritating as hell to go out in the morning and find that deer have devastated our holly, privet, and other evergreen shrubs.

It makes me wish I had caught one in the act with a large stone in my fist, which I could ricochet painfully off its butt. But when my wave of fury has subsided, I feel sympathy for their plight. What kinds of desperate actions might I take, if I were starving? I try to let go my ire at the severe damage they've caused. After all, most of those shrubs will probably recover next spring... or so I fervently hope.

But I can't help wishing their stolen meal gives them a big bellyache. If so, it might deter them from returning and finishing off what little of the plants they spared.

After Masting Aftermath

As I was composing the earlier masting story ("Masting Aftermath", posted 2-3 weeks ago) about our local oak trees, I read an article in the autumn 2012 issue of Living Bird magazine (from Cornell University), on a similar process that is unfolding in the western US. It’s another fascinating tale about the close relationship between animals and trees that periodically mast—this time in the higher elevations of Arizona and New Mexico. It’s a very intimate alliance that has been forged for millions of years between two species that even share the same name: the pinyon pine and the Pinyon Jay. (It’s an interesting byproduct of scientific custom that the bird’s name merits capital letters, while the tree must suffice with lower case letters.)

The symbiotic partnership between the bird and the tree has evolved over time, to the point that today, neither one of them can survive without the other. It is referred to by biologists as a mutualistic relationship—wherein each species derives benefit from their interdependence. The Pinyon Jay’s beak is long and sharp, having evolved specifically to extract seeds from pinyon pine cones. The seeds are very nutritious, but when not available, the birds nearly starve and their chicks—if they have any that year—will not survive.

As part of its bargain, the bird will plant the tree’s large seeds at distant locations, caching thousands of them during the years when the pines mast. The Pinyon Jay has evolved a special throat pouch, into which it can stuff over four dozen seeds! (And any one seed nearly fills its bill!) Monogamous mates will jam their pouch with the plentiful seeds and then fly off, wing-to-wing, and carefully cache the seeds, poking them into the ground. They specifically choose a location where no pinyon pines currently grow. (If that’s not a wonderful example of inherent intelligence, I don’t know what is!) Even though the bird’s memory is so good that researchers have determined it later retrieves some 95% of all its hidden seeds, a few do get forgotten, and some pinyon pines may later sprout in a new location.

This old partnership is in peril, however—threatening both the tree and the jay. Pinyon pine habitat is dramatically diminishing, as development, forest fires, and climate change take their toll on the trees. Recent dry years have fostered more fires; and those fires have worsened because of mistaken forest management in the west, that has discouraged forest fires in recent years and allowed an abundance of dry tinder to accumulate. Conservationists have monitored an alarming decrease in the population of both bird and tree.

The situation is aggravated by climate change—which is causing droughts and heat to worsen. The fates of the Pinyon Jay and the pinyon pine—inextricably linked to each other—is shaky. There is a ray of hope here, however. The mutualistic connection between bird and tree has existed for millennia, and as climate change occurred in past eras, the pines were moved to more favorable locations, thanks to the propensity for the Pinyon Jay to cache seeds in virgin territory.

Will the Pinyon Jay be smart enough (they are a corvid, like crows, and are very intelligent) to find favorable new habitat for the pine, as climate change increases? The future is very uncertain for these two intertwined species. It’s just one more example of the threat to many of nature’s species, as the globe warms and weather becomes increasingly chaotic.

Masting Aftermath—Part 2

Another remarkable facet of the masting process is that oak trees somehow communicate with each other, so they all mast simultaneously. If instead, a tree created an abundance of acorns solely on its own schedule, the widespread acorn abundance would never occur. It is not known exactly how the trees cooperate, but it seems likely that they do so by floating chemical signals on the wind. Oak trees for thousands of acres around get in sync with each other and mast together, collectively outwitting the local critters.

The animals that are enjoying the masting feast around here are those mentioned earlier (squirrels, mice, deer, and blue jays), as well as pigeons, ducks, woodpeckers, and bears. In fact, long ago, farmers would release their domestic pigs in the forest in masting years, to fatten them up for free. The acorn nut is packed with nutrients: proteins, fats, carbohydrates; and minerals like calcium, phosphorus, and potassium.

The rub for the animal diners is that that the oak tree also imbues the acorn with tannins; they taste bitter and mess up an animal’s gut, preventing most of these nutrients from being absorbed. Clever animals have evolved a counter tactic by burying the acorns or placing them in an exposed location where rain can slowly leach some of the tannins out. American Indians—a very clever animal—used to soak cracked acorns for days in water, to make them more edible.

So, what will be the aftermath of a masting year around here? Obviously, the oak trees “hope” that come spring we will see many small oak saplings popping up—some to become mighty trees one day and keep the oak forest in perpetuity. As to the acorn-eating critters, they will eat well this winter and probably produce a prodigious amount of offspring next year. Come next fall, they will encounter harder times, however, when no masting happens, and some of them will perish. That’s the way of nature. There’s no cruelty or design to the process. Some critters must die for other to live. It’s part of the great recycling program.

There is one more interesting aftermath of a masting year that I recently discovered, while talking to a neighbor. He is an excellent hunter and keeps his family’s freezer well stocked with venison. He’s found that deer hunting this year is a little different. He says that normally he can perch in his tree stand and in time, deer will wander by, as they browse for food. This year, however, the deer aren’t moving around much, since they can stay in one location and chow down on an abundance of acorns. He has to go find them. Next year, when acorns are back to normal, he may once again be able to hunker down in his tree stand and have them come to him.

Masting Aftermath—Part 1

This fall was a huge masting year for local oak trees around here. The number of acorns they put out must be more than 20 times the normal crop! I have to be careful walking in the woods, lest I step on a cluster of acorns and watch my feet slide out from under me—as if I had stepped on a banana peel or a bunch of ball bearings on a concrete floor. The local acorn-munching animals—squirrels, mice, deer, and blue jays—will be fat and happy all winter. Their larders will be overflowing and the forest floor will still remain peppered with jillions of leftover acorns.

And that, of course, is exactly why nature evolved the masting process: to create such an overabundance of acorns every few years that the voracious animals can’t possibly eat them all. It’s a way that the oak trees ensure the future of the oak forest—all those leftover acorns will result in an abundance of oak saplings next spring.

There is no intent involved in this process, no plan; no design to seek out a desirable spot. It’s more a case of creating an abundance of seed… most of which will die or get eaten; a tiny fraction will survive and grow. Similarly, fish and other species generate a huge amount of eggs, with the expectation that a tiny fraction will survive and carry the species on.

People have known about this oak masting process and have tried to predict when a such a year will come along. But the oaks even outsmart humans. Europeans have attempted for a few hundred years to forecast the coming of a masting year, without success. Nature’s intelligence remains unchallenged.

Some tree species—such as maples, sycamores, and poplars—distribute their seeds with the help of the wind. It does a tree no good if its seeds drop close to the parent. That’s competition that the parent doesn’t need (as well as the necessity to avoid inbreeding), and the offspring will lose the struggle for survival to the parent. So nature’s wisdom has evolved various methods to disperse the seed some distance away—to a more nurturing location or even to transport the species to an entirely new location.

A maple seed is a beautifully designed helicopter-like wing that spins as it falls to the ground—slowing its descent, so as to allow any wind gusts that may come along to float the seed off at a distance. The fat acorn, however, drops straight down, so nature has evolved another way to disperse them: various animals do the job of transporting the acorns away from the parent. Many acorns don’t even get a chance to drop: blue jays will remove them directly from the tree and spirit them off to some distant lair.

Squirrels cache most of their acorns in widely scattered hiding places. Although they have an excellent memory for their secret spots, not every acorn will be retrieved later and eaten. What’s more, the squirrel usually buries the seed, so if an acorn gets forgotten, it’s in the perfect underground location to sprout and grow.

More on masting next time…

Two Months After the Mast—Part 2

I looked last time at the need for people to predict the coming winter’s severity by consulting folk omens. It was first the wooly bear caterpillar. Now the masting of acorns…

Another favorite winter prophecy is the size of the fall crop of acorns. This story goes that if a hard winter is coming, Mother Nature is planning ahead for the protection of her charges. She’s directed the oak trees to grow an extra large batch of acorns so the squirrels, mice, deer, and turkeys will have enough to eat, to get through the coming severe winter. It’s nice to think that nature does such a kindhearted job of planning, so all her critters are well cared for.

Squirrels, the belief goes, return the favor by helping to grow more oak trees, when they bury acorns and then forget where some of their stash is. Well, there’s a little truth to that, but your average squirrel has a better memory than this gives it credit for. Moreover it kills far more acorns than it plants—either by eating them or simply biting into them and destroying the seed. The squirrel is more a foe of the oak, than a friend. In turn the oak would consider squirrels to be a menace—not a friend to feed.

So what’s going on? A heavy acorn crop is an example of the genius of Mother Nature, but not as a prognosticator of winter. Instead, it’s her way of ensuring the survival of the oak forest. A bumper harvest of acorns is called “masting.” If oak trees were to put out the same number of acorns every year, the squirrel population would stabilize at a level that would see most all acorns consumed. If there were more squirrels than that, some of them might starve; fewer in number and they’d quickly multiply, with all those extra nuts available.

The oak survives by keeping squirrels (and other acorn-eating critters) off balance. The trees put out a conventional (even predictable) supply of acorns for several years, fooling the eaters into thinking that it’s all they’re gonna get. Then, when the animals are looking the other way, the oaks surprise them by masting—producing a copious crop of acorns and carpeting the forest floor with them. The animals may gorge themselves, but cannot eat them all. Some acorns will survive and sprout new oaks. Since oaks live for so long, they need to mast only every few years.

One marvelous feature of the masting process is that most all of the oak trees in a locale will mast the same fall. You can imagine what would happen if the trees didn’t coordinate their crop: randomly scattered oaks would mast when their cohorts would be taking it easy. Such randomness would negate the masting effect. But oak trees are in unison when they mast. How do they do this? We don’t know for sure, but plant research is showing us that trees communicate chemically with each other. They do this in defense of insects—to alert their buddies about invasions. Might they use the same technique to coordinate their masting?

I sure don’t want to take the fun out of checking out wooly bears and monitoring the abundance of acorn crops. Being attentive to nature is a wonderful thing. I love to examine those cute caterpillars, as well as marvel at the abundance and many shapes of acorns during a mast. We might be careful, however, about projecting our idiosyncrasies and hankerings onto Mother Nature. She’s beautiful enough in her own right, that we don’t have to dress her up in anthropomorphic clothing.