How to Manage Pests

UC Pest Management Guidelines

Citrus

European Starling

Scientific Name: Sturnus vulgaris

(Reviewed 7/16, updated 7/16)

In this Guideline:


DESCRIPTION OF THE PESTS

Starlings are dark colored birds with light speckling on the feathers. They are about 7.5 to 8.5 inches long with a short tail. They have a long, slender yellow bill in summer and a dark one during the winter. Starlings have a wide habitat range but prefer areas with trees. If their excrement or droppings contact the fruit, it will cause unsightly blemishes and may transmit diseases.

Starlings are an invasive, exotic species and can be lethally removed at any time.

DAMAGE

Large flocks of starlings may choose to roost in citrus orchards. If their excrement or droppings contact the fruit, it will cause unsightly blemishes and may transmit diseases.

MANAGEMENT

Biological Control

Natural predators such as raptors and bobcats will feed on some of the smaller bird species, although these numbers mean little for controlling such bird pests.

Cultural Control
Habitat modification

Always consider habitat modification as a first step for controlling bird pests.

  • Look for and eliminate brush or pruning piles, stacks of irrigation pipes, piles of boxes, etc., where birds may rest and nest.
  • Consider removing roosting trees along perimeters to reduce bird invasion into fields.

However, there are few situations when habitat modification can be used to control high bird numbers. As such, alternative control methods will likely be needed.

Exclusion

Netting is often used only for high value crops. Be sure to extend netting to the ground and tie off all ends to stop birds from entering underneath.

Monitoring and Treatment Decisions

Count birds weekly to help you determine when damage will occur so you can take action early. This is particularly important to reduce damage to fruiting buds and newly sprouted row crops.

  1. Watch for bird movement into or within the field.
  2. Keep track of species, numbers, and location if you have had substantial damage in the past.
  3. As fruit begins to ripen or as the nuts develop, look for fruit or nuts that are damaged or that have been knocked from the tree or vine.

These records will help you plan control strategies in advance and assess the effectiveness of previous control actions.

Frightening devices

The most effective way to frighten birds from a field is to use a combination of noisemakers and visual repellents such as mylar streamers and "scare-eye" balloons. For example, scare-eye balloons may be attached to trees or posts that are next to electronic distress call devices. This combination may increase effectiveness over using either approach by itself. For maximum effectiveness, rotate from one type of frightening device to another and do not use one combination of devices for more than a week; otherwise, birds will become used to it.

Common noisemakers include roving patrols of bird bombs and shell crackers. Stationary devices such as gas cannons and electronic distress calls also provide relief. These stationary devices are most effective when you have at least 1 device per 5 acres and when they are elevated above the canopy.

Regardless of the approach used, pay attention to bird responses when using frightening devices. When birds no longer respond negatively to a specific approach, you must switch to a different frightening tactic to continue to scare birds out of the field. At best, an appropriate rotation of frightening devices will control bird pests for a few weeks. Therefore, only use these scare-tactics when needed to prevent birds from habituating to these auditory and visual repellents. Additionally, once birds become accustomed to feeding in a field, frightening tactics become much less effective. Therefore, have frightening devices ready to implement before damage occurs so that birds can be deterred right at the onset of damage.

Shooting

Birds that invade orchards in small numbers, can often be controlled by shooting. Check with California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, and county agricultural commissioner officials before shooting any birds as depredation permits are often needed.

Where permissible, occasionally shooting at a few birds will increase the effectiveness of your noisemaking techniques, especially if noise makers go off at the same times as the actual shots, because birds will begin associating loud noises with the real hazards of firearms.

Trapping

Trapping can be an effective way to control starlings, especially if conducted over a relatively large area such as several orchards or vineyards. The most effective trap for these species is the modified Australian crow trap.

Successful trapping must take into account the behavior patterns of the birds being controlled. These traps use live birds as decoys to attract additional birds. Therefore, place traps in suitable locations with adequate food, water, shade, and roost locations to keep the trapped birds alive.

Trapping is best carried out by someone experienced with the technique.

Trapped birds are usually euthanized through the use of a CO2 chamber. Leave some birds alive to serve as future decoys.

Repellents

Chemical repellents rely on objectionable tastes, odors, or learned aversions to deter birds from consuming or damaging fruit.

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Citrus
UC ANR Publication 3441

Vertebrates

R. Baldwin, Wildlife, Fish and Conservation Biology, UC Davis

Acknowledgment for contributions to Vertebrates:
R. E. Marsh (emeritus), Wildlife, Fish and Conservation Biology, UC Davis
T. P. Salmon (emeritus), UC Cooperative Extension, San Diego County
M. W. Freeman, UC Cooperative Extension, Fresno County

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