Identification | Biology | Damage ID | Management |Handling

Overview of Damage Prevention
and Control Methods

Habitat Modification

• Deep ponds with steep banks
• Reduce number of fish in affected body of water

Exclusion

• Enclose affected area with mesh netting

Frightening

• Red or green lasers
• Amber barricade lights
• Strobe lights
• Propane exploders
• Pyrotechnic devices
• Water sprays

Repellents

• Methyl anthranilate

Toxicants

None are available for the control of herons. 

Shooting

• 12-gauge shotguns
• .22-250-caliber rifles.

Trapping

Check with the state agriculture or wildlife department or USDA-WS.

Damage Prevention and Control Methods

With the exception of total exclusion, single control methods rarely solve a bird problem. Results obtained from nonexclusion techniques may vary.  

Habitat Modification  

Dig deep ponds (3 feet or more) with steep banks to discourage herons and egrets. Ensure fish have plenty of oxygen to prevent them from feeding at the surface where they are more vulnerable. Reducing stocking rates may make ponds less attractive to depredating birds. 

Exclusion 

Selection of a barrier system depends on the expected duration of damage, size of facility, and whether the barrier will interfere with other operations. Other considerations include possible damage from severe weather and the barrier’s effect on the appearance of the site (aesthetics) in visually sensitive areas. Any physical barrier control system must be constructed so that it does not become a lethal hazard to birds, especially to threatened and endangered species. 

The complete enclosure (caging) of ponds and/or sensitive areas with screen or net (1- to 2-inch mesh) is the most effective way to stop heron predation. It is not practical, however, for protecting most ponds larger than 5 acres.  

Overhead wires can discourage birds from entering a feeding zone or perching nearby. Space lines 1 to 2 feet apart at most. Install bird spikes to prevent perching. 

Frightening Devices 

Frightening devices typically disperse birds for a limited period of time. To increase effectiveness, vary the kinds, number, and locations of methods used. Consult manufacturers for details on use and safety requirements. Communities may prohibit the use of devices that disturb others. 

Lasers, both red and green, and bright flashing amber barricade lights will frighten herons. Human effigies and strobe lights will disturb herons as well.  

Propane exploders and alarm or distress calls will cause herons to flee an area. For best results, broadcast distress calls as birds begin to arrive. A timing device can be used to play calls at predetermined intervals. Lengthen the time between broadcast intervals as much as possible while still achieving the desired response. Birds habituate to distress calls if played frequently or over a long period in the same location. Ultrasound has not been shown to be effective.  

Pyrotechnic devices such as shell crackers and bird bangers will disperse herons. Follow safety instructions and consult with local law enforcement prior to use.   

Water spray from rotating sprinklers placed at strategic locations may frighten birds for short periods. Motion-activated sprays work best.  

Repellents 

Repellents with the active ingredient methyl anthranilate are available for use against herons. The product must be aerosolized and inhaled by the birds to obtain the repellent effect. Repeated treatments are required.  

Toxicants 

None are available for the control of herons. 

Shooting 

Shooting can be effective in reducing populations of herons. Appropriate firearms include 12-gauge shotguns and .22-250-caliber rifles. Try to shoot when herons are hunting. Consider the risk of ricochet. Consult state and local laws before shooting to ensure legality.  

Trapping 

It is illegal to trap fish-eating birds without a permit from the USFWS. Check with the state agriculture or wildlife department or USDA-WS before trapping birds that are causing damage at aquaculture facilities.