Avian Electrocution on Power Infrastructure

Avian electrocution is the injury or death of a bird when its body completes an electrical circuit across points at different electric potentials. Large birds are especially vulnerable because their wingspan can simultaneously reach multiple electrical components during perching, landing or take-off.

How the electrical pathway forms

A bird resting only on one conductor is ordinarily safe because its contact points are at nearly the same potential. Electrocution occurs when the bird makes simultaneous contact and current passes through its body.

• In phase-to-ground contact, the bird touches an energised conductor and a grounded pole, cross-arm, transformer casing or other hardware.
• In phase-to-phase contact, the bird bridges two energised conductors at different potentials.
• An electric arc may form without complete physical contact if the bird reduces the air gap sufficiently for current to jump across it.

Why large birds face greater risk

Risk depends strongly on pole design, conductor separation and the position of grounded equipment, not merely on nominal voltage.

• Large wings, long legs or an extended neck increase the chance of bridging conductors or reaching grounded hardware.
• Landing, take-off, wing-stretching, nesting and balancing movements enlarge the bird's effective contact span.
• Structures with closely spaced conductors, exposed jumpers, switches or transformers can create dangerous contact combinations.
• Wet feathers or wet nesting material can increase conductivity and facilitate current flow.

Conservation significance and prevention

Electrocution differs from power-line collision, in which a bird is injured by striking a wire without necessarily completing an electrical circuit. For slow-breeding large birds such as vultures and raptors, repeated infrastructure-related deaths can worsen population pressures.

• Safer designs increase separation between energised and grounded components or place them beyond a bird's reach.
• Retrofitting can use appropriate insulation covers, guarded jumpers and transformer terminals, or safe alternative perches.
• Risk mapping and correction of repeatedly hazardous poles allow mitigation to focus on electrocution hotspots.