Avian Protection Plan

Avian Collisions

Bird injury and mortality can result when birds collide with power lines. Collisions occur most often in areas where a transmission line intersects bird breeding and feeding areas, such as bodies of water or wetlands. Power lines are often difficult for birds to see and can sometimes appear invisible due to background or low light conditions. The risk is highest for waterfowl and water birds such as ducks, geese, herons and cranes, as they are not able to maneuver quickly around the lines.


AltaLink installs bird markers at high-risk collision locations. A risk assessment of AltaLink’s existing transmission lines was completed in 2007 to determine which segments of newer lines are at high-risk. For new lines, AltaLink has developed a standard that ensures all new lines are adequately marked and protected.

Frequently Asked Questions

How many birds collide with power lines each year?

There is no easy way to get exact numbers on bird collisions. For existing facilities, AltaLink aims to identify high-risk areas for collisions by conducting bird surveys, and has developed a computer model to help identify these areas. For new construction, all proposed power lines are assessed for their potential for bird collision risk and mitigated accordingly.

What does AltaLink do to prevent bird collisions with power lines?

All proposed power lines are assessed for their potential bird collision risk. New and existing lines in high-risk areas, such as those spanning bodies of water or in close proximity to protected wetlands, will have markers to make the lines more visible to birds. AltaLink uses bird diverters on high-risk lines to increase visibility and minimize avian collisions.

What type of markers does AltaLink use to reduce bird collisions?

AltaLink uses two types of marking devices, the bird flight diverter (BFD) and the Firefly. Both the Firefly and the BFD have been shown to reduce collisions by 60 to 90 per cent.

The BFD is a small spiral device that wraps around the overhead shield wire. It works by providing a visual image that helps migratory birds avoid collisions. The BFD is used in windy areas, such as Fort McLeod, Lethbridge, and Crowsnest Pass.

The Firefly is a reflective tag that hangs from the power line. It has the advantage of being visible in low light conditions when collisions are most common. In addition, the Firefly glows at night for up to ten hours, making it ideal for protecting birds that migrate at night.

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