Description of the Pest
Although jackrabbits are the most common of the rabbit-type pests, they are technically classified as a hare. Jackrabbits:
- About the size of a large house cat
- Very long ears
- Short front legs
- Long hind legs
Jackrabbits live in open areas of the Central Valley, coastal valleys, and foothills and are active all year from early evening to early morning. They are seldom found in dense brush or woodlands. A good sign that jackrabbits are present is their coarse, circular fecal droppings or pellets found scattered over an area.
They make a depression underneath bushes or other vegetation where they remain secluded during the day. Jackrabbits breed from early spring to late summer.
Females may produce more than one litter a year, especially where irrigated crops are available. The average litter contains four pups, which are born fully haired, open eyed, and become active within a few hours.
Cottontail and brush rabbits are smaller than jackrabbits and have shorter ears. They nest where thick shrubs, woods, or rocks and debris provide dense cover. Their young are born naked and blind and stay in the nest for several weeks.
Rabbits are active all year. Jackrabbits frequently damage crops bordering open areas, such as grassy fields and rangeland. Cottontail and brush rabbits prefer crops near brushy habitats, ravines, riparian areas, and woodlands favored by these species.
What rabbits eat is variable depending on location and the availability of appropriate plants. They prefer succulent green vegetation; grasses and herbaceous plants typically make up the bulk of their diet. Feeding usually begins during the evening hours and continues throughout the night into the early morning. Rabbits do not need to drink water.
If food and other necessary resources are found in one place, rabbits will stay in the area. If food and areas for shelter are separated, they will move between these areas in the morning and evening. Daily travel by jackrabbits of 1 to 2 miles round trip between these areas can occur. These travels are habitually made on the same trails every day, producing noticeable paths through herbaceous vegetation.
Jackrabbits, cottontails, and brush rabbits may damage young trees and vines. Rabbits may chew and remove bark and clip off branches within their reach to eat buds and young foliage. Trunk girdling is usually higher on the trunk than damage caused by meadow voles. The damage appears as vertical lines or grooves in the bark. Rabbits usually do not present a serious problem for older trees and vines. Rabbits may also gnaw on drip irrigation lines. They often live outside of orchards, vineyards, and crop fields, moving in to feed from early evening to early morning. They damage plants primarily in winter and early spring, when other sources of food are limited.
Jackrabbits can carry tularemia, otherwise known as rabbit fever. This disease is relatively rare in humans but can be contracted by handling an infected rabbit with bare hands or by eating insufficiently cooked rabbit meat. Do not handle rabbits with bare hands.
Rabbits are active all year but damage trees and vines primarily in winter and early spring when other sources of food are limited. Manage rabbits before severe damage occurs. Common control methods for rabbits include fencing, trunk guards, repellants, baiting, trapping, and shooting depending on the species and crop. Unfortunately, habitat control and trapping are not typically effective for jackrabbits given their ability to cover great distances between forage and shelter locations. The choice of control method should depend on the urgency of the problem and the situation.
Predators such as coyotes and hawks are usually not sufficient to effectively control rabbits. Although these predators consume a number of rabbits, it is usually not adequate to keep populations low enough to eliminate the need for additional control measures.
Rabbit-proof fencing prevents damage to young fields, orchards, or vineyards.
- Make the fence at least 3 feet tall using woven wire or poultry netting with a mesh diameter of 1 inch or less.
- Bend the bottom 6 inches of mesh at a 90-degree angle and bury it 6 inches deep, facing away from the area to be protected, to keep rabbits from digging under the fence.
If you are building a fence to exclude deer, and rabbits are a potential problem, it is a good idea to add rabbit-proof fencing along the bottom. Unless you are already building a deer fence, the cost of a rabbit fence may be prohibitive for a large orchard or vineyard when you are only going to need it for a few years. Individual tree guards are a good alternative, particularly if damage to vines and trees is focused on the perimeters of orchards and vineyards.
Tree guards are useful when planting new orchards or vineyards or replanting trees or vines in established areas. Cylinders made from wire mesh or some hard plastics provide the best protection against rabbits. Cardboard or heavy paper can also be used, but rabbits may chew through these.
- Make the cylinders at least 2.5 feet tall to keep jackrabbits from reaching foliage and limbs by standing on their hind legs.
- Secure the tree guards with stakes or wooden spreaders.
Use smaller-mesh wire and bury the bottom few inches of the cylinder if you also need protection against voles.
Rabbits often invade from adjacent fields, but unless the land is under the grower's direct management, habitat modification of the outlying habitat is usually impractical. The removal of preferred foods such as cover crops and weeds may reduce the number of rabbits that visit the crop and make them easier to detect. However, removal of vegetative cover may temporarily increase damage as the desired crop would be the only food source left for rabbits. Therefore, except for removal of old prunings and brush piles, habitat modification to reduce damage is rarely practical.
Monitoring and Treatment Decisions
Rabbits often breed, bear young, and live outside fields, orchards, and vineyards. They move in to feed at night so you may not see them during daylight hours. Therefore, monitor in the early morning, late evening, or at night (using a spotlight):
- Inspect young trees and vines periodically for feeding on bark to catch a problem early.
- Look for clipping of small, low branches and leaves as tree breaks dormancy.
If you find damage:
- Look for droppings and tracks that indicate rabbits may be the cause. Voles also chew the bark from the trunk, but the bark damage caused by rabbits extends higher on the tree and the tooth marks are distinctly larger.
- Monitor the perimeters in early morning or late evening to see where rabbits are entering and to get an idea of how many are involved.
- Estimate the number of jackrabbits at night by using a spotlight and looking for "eye shine."
Poison baits may be practical for controlling large numbers of rabbits in large areas. Before baiting, consult the county agricultural commissioner for restrictions related to endangered species. Follow label directions carefully.
Only multiple-dose anticoagulant baits (i.e., chlorophacinone* and diphacinone*) are registered for use against rabbits. These baits are available from many county agricultural commissioners' offices. All field-use anticoagulant baits are now restricted use materials; you will need to be certified to use these baits for rabbit control. They come in grain formulations that may be used along field edges, but not within the field itself.
Multiple-dose baits for rabbit control must be placed in bait stations specifically designed for rabbits.
- Place bait stations containing bait near trails and secure them so they cannot easily be tipped over.
- Use as many stations as necessary to ensure that all rabbits have easy access to bait, spacing them 50 to 200 feet apart along the perimeter where rabbits are entering the field.
- Inspect the bait stations every morning for the first several days to keep bait supplies replenished; it may take this long before the rabbits become accustomed to feeding at the stations. Increase either the amount of bait in the stations or the number of stations if all the bait is consumed in a single night.
- Replace any bait that becomes wet or moldy.
- Continue baiting until feeding ceases and you no longer observe any rabbits.
It usually takes 2 to 4 weeks or more before results are seen with multiple-dose baits.
Bait should be covered or removed during daylight hours to prevent consumption by diurnal seed-eating birds. Make sure to take precautions to prevent domestic animals and wildlife from having access to the bait. Dispose of unused bait properly at the end of the baiting program. When baiting for rabbits, you should remove all aboveground carcasses by burying them underground, or by bagging and disposing them in the trash. This will reduce potential secondary poisoning hazards.
Shooting, applying repellents, and trapping may provide effective control for low numbers of rabbits or may be used to temporarily reduce damage until other measures such as fences or tree guards are installed.
- When low numbers of rabbits are present and causing damage, shooting can be an effective control if shooting is allowed in your area. If only a small number is involved, shooting may be all that is necessary to prevent significant damage while crops are susceptible. For best results, patrol systematically in the early morning or at dusk.
- Keep in mind that lead ammunition is being phased out across the state. Additional information on this lead ban can be found at Department of Fish and Game website.
Repellents are occasionally effective at deterring rabbit damage to some crops, particularly orchard and vine crops. However, no effective rabbit repellents are available for use in most vegetable and forage crops. To apply repellents in orchard and vineyard crops, spray or brush the repellent on trunks during the dormant season or on foliage or trunks during the growing season. Labels specify the proper application method, rate, and timing. Repeat applications as needed to protect new growth and to replenish any repellent that is washed off by rain or sprinkler irrigation. Effectiveness of repellents often is dependent on availability of alternative food sources. If additional food sources are abundant, repellents sprayed on target plants may be effective. If additional food sources are scarce, repellents may have little effect.
Trapping generally is ineffective against jackrabbits because they do not readily enter traps. Box-type traps, especially the Critter Getter DK- 3 baited with apple slices or dried apricots, can provide effective control of cottontails or brush rabbits when populations are small. Pre-baiting with a small amount of bait has been found to improve results.
* User must be a certified applicator or be under the supervision of someone who is. Some products also require a permit from the county agricultural commissioner for purchase or use.