Why Do Birds Roost on Power Lines?

"Birds of a feather, flock together," and they often flock to power lines. It is an everyday phenomenon to see birds perching on electric lines. Just as some people are gregarious and others, loners, some bird species roost on high with dozens of their kind, while others remain alone. We see power lines as conveyors of electricity, but birds view them only as places to perch.

  1. Considerations

    • Location, location, location. Birds--even the biggest species--are short compared to the trees and shrubs around them. Since power lines are always well above the ground brush, birds roosting on the lines gain views on all sides. The less trees that are found in an environment, the more attractive the electric lines become for perching or roosting.

    Protection

    • A bird on the ground is a bird in danger. It can be surprised by predators or crushed by a passing vehicle. In attaining height, a bird eliminates many of these risks and is able to keep an eye out for those threats that remain, such as hawks or owls. Trees primarily serve that role but birds are adaptable and have learned to substitute telephone and power lines where forests are sparse or unavailable.

    Hunting

    • A raptor has excellent vision and depth perception.

      While some birds spot prey during flight, others prefer to hunt from a standstill, searching the landscape with their keen eyes for rodents or other prey. These are the raptors that perch on poles or electric lines. The cleared area around power lines increases visibility for birds of prey.

    Misconceptions

    • Since birds roosting on power lines is such a common sight, it is easy to conclude that they cannot be injured by the electrical current. This is not true. According to the U.S. Geographical Survey, electrocution is a serious hazard to wild birds, especially in open, treeless habitats. Golden eagles have been the most affected, but large buteos, falcons and large owls are also at risk. If any portion of the perched bird's anatomy touches a second energized part of the power line, electricity flows through the bird's body, killing it.

    Consequences

    • Birds roosting on transmission lines can also cause damage and inconvenience. Bird droppings can pollute the insulator disks, causing electrical faults that have a detrimental impact on the quality of electrical supply.