Mammals in the Garden

Not counting gardeners, there are several types of mammals that may turn up in your garden. Some can be helpful, others can be a royal pain. ​

Deer visits back garden  (Graham Richards) CC BY-SA 2.0

Mammals are warm-blooded and more or less intelligent. This can make excluding them from certain areas of the garden problematic. In most cases, there are ways to work around pesky mammals in the garden, without losing your mind or getting in trouble with local law enforcement.

Speaking of law enforcement, before you go trapping, shooting, poisoning, or otherwise dispatching wildlife, you need to track down your local laws and obey them. The low level squirrel feud can turn into a legal nightmare if improper methods are used against them. It’s not worth it - regardless of how tempting it may be when they take your last juicy pears for the umpteenth time!

So, let’s see which animals might end up in the garden and how to protect your plants against them. 

Bats

There are three major types of bats found in North America: leaf-nosed bats, vesper bats, and free-tailed bats. These bats are primarily insectivores, capturing insect pests, such as moths, wasps, flies, mosquitoes, in flight, or capturing beetles, ants, and other insects off of leaves or from the ground. This makes bats welcome guests in the garden, though they will sometimes eat ripe fruit. [Who can blame them?] You can attract bats to your garden for the evening shift by installing a bat house.

Little brown myotis (SMBishop) CC BY-SA 3.0

Deer

Deer are the bane of gardeners wherever they are found. These animals can leap small buildings in a single bound. Oh, wait, wrong story. But deer can wipe out an orchard, garden, or landscape, between feeding and trampling, in short order. Really high fencing (and I mean 7- or 8-feet high) might block deer. If your garden is on a slope, you will need fencing that is 10- or 11-feet high! Loud, scaring devices and various repellants can also be used to try and block these determined garden pests, but the effectiveness of these methods doesn’t last very long.

Mice

In California, we have deer mice, house mice, and meadow mice, also known as voles. Deer mice and house mice are mostly seed eaters that can wipe out a garden crop before it even starts. Voles are herbivores that will eat your bulbs, tubers, artichoke, beets, Brussels sprouts, celery, cauliflower, sweet potatoes, lettuces, tomatoes, turnips, cabbages… well, you get the idea. If that weren’t enough, voles will also chew the bark off your fruit and nut trees.

Deer mouse (6th Happiness) CC BY-SA 3.0

While poisons do kill mice, those poisoned mice can then be eaten by other wildlife, or your pets, so I urge you to avoid poisons. And those sticky boards, well, those are just cruel. Also, as the animal struggles to escape the glue, they tend to urinate and defecate and those materials then get slung around as the animal continues to struggle. Instead, good old fashioned mouse traps are still your best bet. They are usually an instant death and generally not very messy. Since all mice can carry hantaviruses, be sure to wear non-fabric gloves whenever handling mice, materials mice may have urinated on, or mice droppings. Also, be sure to thoroughly disinfect any areas inhabited by mice.

Eastern mole (Kenneth Catania, Vanderbilt University) CC BY-SA 3.0

Moles and shrews

Shrews and moles may look like mice with deformed noses, but they are not rodents. They are more closely related to hedgehogs. There are 13 shrew species and 4 moles species in California, and they spend most of their lives underground, digging burrows and eating. For their size, shrews have voracious appetites, eating 1/2 to 2 times their body weight each day in worms, insects, and other invertebrates. They will also eat seeds, roots, and bulbs, but mice and pocket gophers are usually the culprits in those cases. Trapping is the most effective control measure, though chemical repellants and noisy, scaring devices can provide some protection.

Opossum

Opossums

Opossums may look prehistoric, but they can do your garden a good service. While they will sometimes eat fresh fruit and vegetables, opossums much prefer rotting produce, ticks, slugs and snails. In my book, that makes them a beneficial visitor. If an occasional tomato is lost, well, it seems a fair price.

Pocket gopher (William L. Farr ) CC BY-SA 4.0

Pocket gophers

Pocket gophers spend most of their time underground, digging burrows that lead to many of your garden and ornamental plants. We have 5 gopher species in California and they all feed on roots from below. They will also grab a tasty plant and pull it below ground to enjoy in relative safety. In a single night, one pocket gopher can destroy an entire garden row. Gopher traps are your best control measure.

​Rabbits, hares, and pikas

Contrary to popular belief, rabbits are not rodents. They are lagomorphs. There, I said it. Now, what are pikas? And what’s the difference between rabbits and hares? Well, rabbits are smaller than hares, and hares, also known as jackrabbits, have longer legs and ears. Also, hares change color with the seasons, while rabbits do not. As for pikas, you probably won’t ever see them because they tend to live at elevations above the tree line, but they are cute. So are rabbits and hares - until they decimate your salad garden or other crops. Keeping rabbits and hares out of the garden is an unending battle. Since they can burrow, fencing alone is not enough. Raised beds with an exclusionary hardware cloth base may be your only real solution if these pests are feeding on your garden. ​

Nuttall’s cottontail (Justin Wilde) Public Domain

Jackrabbit (Ancheta Wis) CC BY-SA 3.0

American pika (Public Domain)

Raccoons

Raccoons are smart. And when they are not attacking your chickens or eating your pet’s dinner, they are probably busy eating your garden fruits, berries, nuts, corn, or other grain. Raccoons are attracted to compost piles, trash cans, and bird feeders. Raccoons may also try using your house, chimney, or garage as a nesting site. While young raccoons are adorable, these nests mean the presence of urine, feces, and disease-carrying parasites. Also, unlike opossums, raccoons tend to carry several diseases, such as roundworm, distemper, and rabies. Raccoons are best controlled with live traps. As a furbearer, raccoon pelts have value, so you can probably find someone who will be happy to discharge a trapped raccoon. Otherwise, you can discretely relocate your visitor somewhere more appropriate, and less destructive. Just be sure to check on your legal obligations before you get yourself in trouble.

Raccoon (David Menke) Public Domain

Rats

Wherever you live, you probably have rats. The two most common types of rats are Norway, or sewer, rats and roof rats. These pests are filthy, destructive, and difficult to get rid of. Rats carry diseases, chew through electrical wires, and can damage your home, along with your garden. Roof rats prefer avocados, berries, citrus, and nuts, while Norway rats prefer meat and grain. Before you protect your garden against these pests, be sure that there are no points of entry to your home. Once your house is secure, then you can start trapping outdoors in earnest.
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Skunks

There are spotted skunks and striped skunks. In either case, it is a good idea to stay at least 10 feet away from the back end of a distressed skunk. [By the way, skunks have terrible eyesight. If you find yourself closer than you would like, be very, very still, or move away very, very slowly. A startled skunk is an unpleasant experience.] Both skunk species will eat pretty much anything: garbage, compost, pet food, worms, fruit, berries, mushrooms, beetles and other insects, lizards, frogs, snakes, and even the occasional bird egg. Since skunks are the most common carrier of rabies in California, along with distemper, canine hepatitis, leptospirosis, and several other diseases, getting them out of your garden (or out from under your porch) is a good idea. This is best done by professionals. Very often, your local Animal Control Office will remove skunks for free. Once a skunk family is removed, it is important to block whatever area, or remove whatever feature, attracted them in the first place. Otherwise, you will just get a new skunk. If you are unfortunate enough to be bit by a skunk, see your doctor right away. Seriously.

Squirrels

There are two major types of squirrels: tree squirrels and ground squirrels. If I didn’t have dogs, I would probably have nothing to show for all my work in the garden because of squirrels. I was surprised to learn that they will eat oranges, tomatoes, blueberries, pears, and more. Adding insult to injury, squirrels will, like birds, often only take a bite or two before moving on to the next delectable piece of fruit, leaving a trail of potential disease behind them everywhere they go. Hardware cloth and chicken wire are the only reliable barriers to squirrel feeding, though I have had some success with a repellant called Bobbex-R.

California ground squirrel (Walter Siegmund) CC BY 2.5

Finally, our pets.


We love our pets. There’s no denying that cats and dogs have a very special place in our hearts. That being said, we do not want cat feces next to our lettuces, or dogs digging up rows of beans or tomatoes. As much as your cat may love being outdoors, researchers at UC Davis have demonstrated that your cat is perfectly happy and actually safer kept indoors. Being stealthy predators, cats can decimate local bird, reptile, and amphibian populations, and we need those other creatures more than your cat needs time outside. Dogs can be trained to provide several beneficial services in the garden. My two dogs will chase squirrels, raccoons, rats, mice, opossum, jays, and cabbageworm butterflies out of my garden. Since most of my gardening is now done in raised beds, I don’t have to worry about the dogs running through them.

While we need to learn how to live and let live, there is nothing wrong with protecting what is yours.  This is especially true for disease carrying pests. In some cases, it is simply easier to fence in your crops with netting and tree cages. For those mammals in the garden that must be killed, please use the fastest, most painless method. 

How do you manage mammals in your garden?