Garden Helpers: Patriotic Ground Squirrels

As we recently celebrated our national Independence Day, so we can’t help but think of our little patriotic friends, the 13 Striped (or “Lined”) Ground Squirrels, who are also called Patriotic (or “Federation”) Ground Squirrels because of their fur’s resemblance to our American flag. It is formally known as Spermophilus tridecemlineatus.

We have many of these and other rodents at our farm because of the almost entire lack of predators. Our neighbors intentionally kill foxes, coyotes, lions, and many other creatures that would eat the rodents, and unintentionally kill hawks, eagles, snakes, and other predators that control rodent populations.

The farming methods of our neighbors are partially to blame for the lack of biodiversity, but the intentional and unregulated hunting of predators for profit, sport and to cause their extinction results in an ecology inhospitable to agriculture. Agriculture that increases biodiversity creates an environment conducive to agriculture.

Some of these predators have valuable skins, but usually they are killed for a perceived danger to domestic animals. It is reasoned that wild dogs and cats could sicken domestic dogs and cats or kill domestic birds (or cattle); the “prairie goats” (antelope) and deer are accused of eating hay and other crops.
However, there are many ways to prevent agricultural damage from predation. Donkeys, llamas, roosters and other guarding and herding animals can work around the clock to protect livestock, and planting in beds and aisles, not tilling in autumn, letting weeds grow and conserving natural areas can reduce herbivorous predation.

The Federation Squirrel poses no real threat to crops, in fact, more than half of its diet consists of those herbivores that would eat our plants. Its favorite herbivores are grasshoppers and wireworms.
The remainder of their diet consists of seeds and grain, and while these can be valuable agricultural commodities, they are more likely to be the seeds and grains from weeds.
Thirteen Lined ground squirrels are omnivorous. Though they prefer mice and grasshoppers, they will eat also caterpillars, beetles, cutworms, ants, insect eggs, mice, earthworms, small birds, and each other. The vegetative portion of the diet includes seeds, green shoots, flower heads, roots, vegetables, fruits, and cereal grains.

They rarely drink water, depending instead on water contained in their food. They cache large quantities of seeds and grass, but never meat. The cached food may be eaten during periods of bad weather or in the late autumn and early spring when other food is scarce.

These brave defenders of our fields will also sometimes eat sprouts. The greatest damage we have received from them is the consumption of 4 squash sprouts – these were tried and disliked. No other damage has been incurred, and because we planted three squash seeds at a time, no loss to production resulted (squash will yield about the same number of fruits per acre with little regard to the number of plants per acre).

These animals seek their food close to their burrows. They mate after they emerge from hibernation in the spring; the female bears 5 to 13 offspring at a time. The 13-striped spermophile has 7 grayish-yellow stripes running down its back, interspersed with 6 stripes composed of spots. Its lower parts are fawn colored.

Patriotic squirrels weigh about 8 ounces (227 g) with a length of about 10 inches (25 cm) including a tail of 3 inches (8 cm). Each front foot has four toes with long slender digging claws. There are five toes on each hind foot.

The thirteen-lined ground squirrel is a grassland animal. Its original range was limited to the prairies of the North American Great Plains. When Europeans arrived and started clearing forests and establishing pastures, the thirteen-lined ground squirrel was quick to extend its range into the new habitat. Today, it ranges from central Alberta, Manitoba, and Saskatchewan in the north to Texas and New Mexico in the south, and from central Ohio in the east to Colorado in the west. The forests of the Appalachian Highlands and the Rocky Mountains have halted their east/west range expansion. There are a few colonies in Venango County, Pennsylvania, the result of introductions made in 1919.

Accordingly, as we reforest our land with cherries, plums, acorns and various other trees, we can expect the populations of the Federation Squirrel to decline. By our reservation of meadows (see this issue’s Letters from Agate), however, this important species will continue to service our crops and protect our trees.

The inconspicuous 2-inch (5-cm) diameter burrow opening is often concealed by vegetation and rarely has soil scattered in front of it like a woodchuck’s burrow. The main entrance plunges down 6 inches (15 cm) or more before angling off into a complex system of galleries and side entranceways. The nesting chamber, about 9 inches (23 cm) in diameter and lined with fine dry grass, is located somewhat deeper than the main burrow system.

We have noticed they will choose as a burrow site a place that shields the burrow’s sight from above, either by a large flowering plant or with a stone. This helps protect them from hawks, owls and other flying predators. They like to keep the entrance to their hole tidy and free of loose dirt by "sweeping" with their back feet. Just inside is the entryway and then the tunnel turns in an "L" shape. This shape helps trick pesky burrowing predators, like the badger, into thinking there is a dead end to the tunnel.

Mating activity begins within 2 weeks after the squirrels emerge from hibernation. Both sexes are sexually active for about 2 weeks. After a gestation period of 28 days, 3 to 14 (average 10) blind, naked, and toothless young are born. Only 1 litter is produced per year. Young ground squirrels weigh about 1/10 ounce (3 to 4 g) at birth. Their stripes begin to appear after about 12 days and their eyes open 28 to 30 days after birth. Young squirrels are weaned and on their own after 6 to 12 weeks, when they dig their own burrow, usually within 100 m of where they were born.. Thirteen-lined ground squirrels are sexually mature at 9 or 10 months of age.

They are true hibernators, allowing their body temperature to drop to just above freezing and their heart rate to drop to as low as 20 beats per minute from their usual 200. During hibernation, S. tridecemlineatus can lose up to 1/3 of its body weight. Food caches are consumed during hibernation arousals, especially just prior to emergence.

Thirteen-lined ground squirrels have excellent senses of vision, touch, and smell. They use alarm calls and other sounds, as well as using special scented secretions, to communicate with other squirrels. They rub glands around their mouth on objects to leave scent marks. They also greet one another by touching noses and lips.

Having grown up in safety, our patriotic friends are not shy at all and will come right up to you as you work to ask you what you are doing! They have not learned to fear the tall grasses and weeds that normally protect our crops. Creatures are normally afraid of the snakes, coyotes or other predators that might be hiding in there, but out here in Agate where most of the predators have been killed, we cannot rely on fear to protect our plants.

It is a good thing, too, that they are bold: our rodent problem would be enormous indeed! When the coyotes, snakes and foxes failed, the squirrel population boomed: squirrels are harder for the predator-killing ranchers to kill!

We are glad to see the return of the snakes, the foxes and coyotes, but rely so heavily upon our Federated friends that we cringe at the thought of what we would do without them.

Yet it is true that these squirrels like grain. 12 of them live near to our barn where our animal feed is made and stored. It sounds like a disaster in the making, but we are able to protect our barn cheaply and effectively, without resorting to killing these magnificent creatures. We do not resort to poisons, gunfire or traps, we do not attempt to kill them at all!

First, we create habitat and refuge for the predators who will control their populations.

Next, we place a bag of old safflower seeds out, somewhat “hidden,” so that the squirrels think that they are discovering a hidden cache. This increases their desire for it: if the seeds were good enough for us to “hide,” it must be good! This does the trick every time. Provide them food to fill up on and you will preserve your crops: give them something cheaper to eat than your precious animal feed!

Safflower, and other grains, may be purchased from Coastalfields or your local elevator or feed store. Really, any grain will do: all rodents LOVE grains. A 50lb bag will allow for about 800, 1 ounce applications. Though Coastalfields grains cost more than those grown by our competitors (who enjoy the benefits of scale economies that come with thousands of acres of production), even at $1.50/lb, each application will cost $0.09.

1 ounce of seed placed far from your crops (in a sheltered area they like to eat in) will cost you less than a dime and will protect your crops for a day. Six months of protection will cost the princely sum of $17.10 per rodent.

Usually a year’s application is not necessary because within a few months of proper farming, predators return and control the rodents.

Compare this to a trap, which usually does NOT work. We will assume, for argumentation, that the trap works 100% of the time, though. Because rodents are wise to traps, presume 6 traps or so are required to be placed around EACH hole the rodent lives in to ensure that the rodent is trapped. We will presume that the rodents have only one hole each. The trap will cost about $0.25 per rodent, and you would need 6 traps x 12 holes x $0.25 = $18. That is $0.90 more than using seeds.

Compare seeds to shooting the rodents. Pretend that you could actually aim tolerably well (they do come right up to you, after all!) and you could destroy one rodent with one bullet. Each bullet costs $0.25, so you’ve come out ahead, right?

But how long does it take you to shoot the rodent? How many hours do you have to wait for the rodent to come up to you to shoot it? Even earning the State’s minimum wage of about $7 per hour, if it took you more than 2 hours and 24 minutes, you’ve spent more on time and bullets than you would have on seed (and still haven’t gotten to your farming yet...).

But what about dynamite, poison gas, or any of the extraordinary unconventional weapons you can use on rodents? What about poisons? Even if you ignore the costs to the environment (which are, after all, real costs that affect your bottom line), they are still more expensive than giving seeds to the animal and waiting for your carnivorous friends to return for lunch.

We pay either the cost of our ruined feed or the affordable dime-a-day in seed. The second method is best: it is cheapest and, by fattening themselves with their greed, they attract the hungry creatures that will eat them. The foxes will have cured the squirrels’ greed and the squirrels will not hunger any more for what is not theirs.

Yet these squirrels are smart enough to know this. Though they could, they do not subside on our grain alone. They eat our weed’s seeds and grains, and the insects that would eat our crops. Through this important work, they so fully discharge their debt of 10 cents per day to make themselves our creditors again!

What better lesson is there for our Independence Day, than those taught by the Federation Squirrel?


Topics: predators , Squirrels , dynamite , rodents , foxes