What is a marmot doing in my yard?

In Idaho, we use the name rockchuck for the yellow-bellied marmot (Marmota flaviventris).  In some places they are also called "whistle pigs".  Marmots are rodents and are the largest member of the squirrel family.   They look like an overgrown ground squirrel with a yellow-tan belly.  Males can weigh as much as 11 pounds.  

Marmots live among rocks where they can find and build burrows.  Luckily, they do not indiscriminately dig burrows in open ground like their eastern "woodchuck" cousins. They are common in Idaho's warm valleys and are often seen in the foothills, even near cities, and also around the edges of lava formations. It is a common site in southern Idaho to see yellow-bellied marmots in springtime sunning themselves on rocks along roadsides.  In the summertime, marmots mostly emerge from their dens and feed at night. For that reason, it is sometimes hard to identify the culprit when damage is discovered in the garden.

Marmots tend to live in social colonies, are prolific breeders,  and can become serious garden pests if present in large numbers.  Marmots will eat any tender, green plants but especially love succulent vegetables.  They are voracious and a few marmots can strip a vegetable garden in a few nights. Marmot damage is unique in that they eat plants to the ground, giving them a "mowed" look. Other pests tend to be selective in what they eat.

Benefits and conflicts

Marmots provide little direct benefit to the homeowner. They can be interesting to observe during the times of the year they are outside their burrows. Conflict with marmots come directly as a result of their tendency to raid the garden and eat anything that looks like a plant, including the lawn.

Strategies for coexistence and control

In agricultural areas, when marmot damage becomes severe, action is taken to eliminate the problem through shooting, gassing, or poisoning. For the homeowner, these options may not be appropriate for a number of reasons. Also, many gardeners are willing to share their produce, as long as the marmots to not take the lion's share. Here are a few ideas for dealing with marmots if they become a problem:

Remove them through trapping: Live traps, baited with succulent leaves or sprigs of clover, can be used to capture marmots, which then can be moved to a more suitable habitat. To keep the pests from returning, relocate them to a place at least five miles away.  

Plant a "marmot garden": If the marmots are not too numerous, you can keep them from damaging precious plants by planting an attractive feeding spot close to the den.  Given their preference, marmots will eat succulent clover over most other types of plants, so a plot of red or white pasture clover would be a good choice for your "marmot garden".

Build a fence: Placing a marmot fence around choice vegetation can be a good alternative, but the job must be done right.  Marmots excel at both digging and climbing.  The fence must made of mesh wire, and be at least 4 feet tall and preferably bowed outward at the top. The bottom must be buried 12 to 18 inches into the ground; if possible, the underground portion of the fence should jut outward to form "L" that will make it harder for the marmot to dig underneath.  In reality, fences are of questionable value in keeping marmots at bay.  One exception to this is the use of electrified fencing with multiple wires spaced from just above ground level to about 2 feet up.

Other measures: Reports in popular press sources suggest other possible measures for chasing marmots from the neighborhood. These include placing mothballs or ammonia-soaked rags down the den entrance, spraying the den area with simulated urine scent of dogs or foxes, or using an an electronic high-frequency noise device placed near the burrow. Although unproven, these tactics may be worth a try.

For more information

Mother Earth News. "Goodbye, Groundhogs", a news article directed at preventing woodchuck damage, but still pertinent for rockchucks: http://www.motherearthnews.com/Livestock-and-Farming/1979-05-01/Goodbye-Groundhogs.aspx

A detailed description of yellow-bellied marmots on Animal Diversity Web: http://animaldiversity.ummz.umich.edu/site/accounts/information/Marmota_flaviventris.html

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