August – Bird and Mammal Pests

Beating the Bugs

Tomato Hornworm illustration — Illustration ©
Melissa Joskow

The information here was originally published in a monthly column on pest control in Between the Rows – A Guide to Vegetable Gardening published by VCE in collaboration with MGNV.

Don’t miss Kirsten’s in depth online class:
What’s Eating My [Cucumbers, Tomatoes, Eggplant, Beans, Squash]? :
Insect Pest Management for the Vegetable Garden

Managing Bird and Mammal Pests

Our two- and four-legged visitors to the garden are often a joy to see, and when we are not BOTH trying to harvest the same crops, most of us would agree that the birds, rabbits, raccoons, and other small mammals are welcome. Because deer cause so much damage and have very different kinds of controls, we will save them for another time, but the problems that many gardeners have are with birds and members of the rodent family. Chief among these are voles, rats, groundhogs, squirrels, and chipmunks. Rabbits are another story altogether.

Birds

Bird damage to apples (Source: University of New Hampshire Extension)

Birds of all kinds enter our gardens on a frequent basis. They are usually good neighbors and can actually provide some help in pest control. Major offenders vary from site to site, but generally problems come from the larger birds that are omnivorous and consume fruit as part of their diet.

Blue jays, starlings, catbirds, and crows are members of the Corvidae family and will often help themselves to ripening fruit just as it starts to turn soft.

In many cases they are attracted to tomatoes for the moisture they contain. Putting out a water feature, a fountain, or a bird bath will help supply those needs. Be sure to clean it once a week to reduce mosquito populations and keep the water safe for the birds.

Sparrows and other ground feeding birds can be attracted to newly planted seed and will sometimes also help themselves to newly emerged vegetables, especially lettuce plants. Covering newly planted rows with fresh straw will protect seeds and young plants from birds looking for a salad bar.

The main tools for controlling unwanted birds in the garden are scare devices, physical barriers, and chemical repellents. Scare devices can be noisemakers, strobe lights, or water sprays. They can be motion detected or set to go off at regular intervals. Low-tech tactics like stringing up shiny foil pie tins that move in the wind can work; a predator effigy like an owl or a hawk can sometimes work, too. If you choose to use netting to exclude birds from fruit, be aware that these nets can sometimes trap birds, snakes, and small mammals inside or underneath the netting.

The bottom-line is that you have to check and change netting and scare devices from time to time. If the scare tactic remains passive and unchanging, the birds will rapidly learn that there is nothing to fear and will move in. Change the pattern of light/noise and change the position or type of scare tactics every couple of weeks for best results.

Rodents

All of the common rodents in our area are omnivorous scavengers and will eat most anything they can find including seed, fruit, stems and leaves, and the occasional meat source including insects and other small animals. Many of these creatures are very smart and quickly find ways to circumvent our best efforts to reduce their depredations.

With all of these, the number one method of control is going to be exclusion. Using raised beds, fencing, containers, netting, and repelling devices are all going to work some of the time. For some of these there are registered repellents that may be effective. Detailed information is available in section 8-1: Other Animals: Conflicts with Vertebrates of the Home Grounds and Animals: 2022 Pest Management Guide. A second tactic that should always be employed is to reduce shelter and other means of accessing protected hiding places and alternate food sources.

Remove tree branches overhanging your home or garden.
Provide roosting sites with a clear line of sight for birds of prey who are happy to swoop to the rescue if they can for their furry meals.
Do not pile boards or logs up near garden sites.
Remove tall brush and weeds along fence rows.
Block, board up, or fence off access to sheds and other structures both above and below the soil line.
Remove bird seed feeders, clean up old or rotten fruit, and grind up vegetable and fruit being added to compost piles for quicker decay.
Encourage snakes and other predators in the garden.

Pine voles create golf ball-sized exit holes in their tunnels.(Source: Barbara H. Smith, ©2017 HGIC, Clemson Extension)

Voles are small mouse-sized plant eaters that will feast on fruit, seeds, roots, leaves, and stems if not controlled. Snap traps and removal of mulch, weeds, brush, cardboard, and wood boards on the ground will reduce populations. Also encourage access to your garden by foxes and birds of prey. Moles are a different creature that prefer to eat insects and worms and live below ground. See photos of voles and moles here.

Ground squirrels that include gray and red squirrels and groundhogs are often blamed for eating garden veggies, tomatoes, and fruits like apples and pears. They are territorial, so reducing their populations simply means that others will move in. Trying to exclude them by netting is difficult. Providing alternative food sources like bird seed, corn, and nuts may divert them from your garden.

Eastern Chipmunk (Source:
Missouri Department of Conservation)

Chipmunks are so very cute but they are tremendously destructive and will gather up freshly planted seeds, eat small cucumbers, and other young vegetables and fruit, and generally feed on above ground plant structures. Rat snap traps are sometimes used for these problem animals.

Rats often require professional control tactics because their numbers are driven by available food sources that are not limited to the garden. They are also quite adept at accessing raised beds, chewing through netting, and even climbing trees. A professional pest management assessment of the population numbers and main food sources will be needed to control garden predation. As control often involves the use of poison baits, care must be taken to limit access to the bait by children, birds, other wild animals, and especially pets.

Rabbits

close up of rabbit on field — Photo by Pixabay on Pexels.com

Bunnies are classified as lagomorphs and are not rodents. Your best options for controlling their feeding activities in your garden will be exclusion, repellents, and perhaps diversions. Fencing will need to be similar to chicken wire with mesh smaller than 2 inches square. For best results fencing around beds should be installed with at least 6 inches of it extending down into the soil and at least 2 feet of height from the outside ground level to the top of the wire. This is still easy for you and others to step over.

Repellents that are effective will have to be reapplied regularly. One that works is pet hair or the scent of dogs or cats in the garden. Common animal product fertilizer products like bone meal and blood meal are effective and contain nitrogen and phosphorous that your plants will appreciate. Chemical products that are available as repellents generally have some kind of protein-based odor component.

Diversions such as providing them with clover patches or overseeding your lawn with clover will provide them with a food source that is more attractive than your vegetables. As with rodents, making an effort to reduce hiding places will pay dividends in reducing your gardens’ attractiveness.