Study reveals mallards' flight responses ineffective in preventing vehicle collisions

Research Highlights Risk to Both Humans and Wildlife, Suggests Need for New Collision Mitigation Strategies

A recent article published in PeerJ Life & Environment has uncovered insights into how mallards (Anas platyrhynchos) respond to approaching vehicles, revealing that these common waterbirds are poorly equipped to avoid collisions, particularly at high speeds. The research, which used both simulated and real-world vehicle approaches, highlights the urgent need for improved methods to reduce bird-vehicle collisions—events that are not only financially costly but also dangerous to both humans and wildlife.

 The study focused on the behavior of mallards when exposed to vehicles approaching at different speeds and under varying light conditions (day vs. night). Results showed that mallards demonstrated a reduced likelihood of attempting escape when faced with simulated nighttime vehicle approaches. However, when they did attempt to flee, they did so with more time to spare compared to daytime scenarios.

“Our findings suggest that the looming headlights of vehicles at night may not be perceived as a significant threat by mallards. The lights visible at night are a more abstract stimulus than a predator or the body of a vehicle visible during the day, and may not provoke the same level of threat response needed to adequately respond. Mallard visual systems may also not  be well adapted to low-light settings or attuned to standard vehicle lighting," said Guenin, the lead researcher. 

Mallards' responses were further tested using real vehicles, where they exhibited an additional concerning behavior—a delayed margin of safety. Both the distance at which birds initiated flight and the time available to avoid a collision decreased as vehicle speed increased. This marks mallards as the first bird species known to exhibit this response to vehicles, making high-speed encounters especially dangerous.

Key Findings:

• Mallards exposed to nighttime vehicle approaches were less likely to attempt escape
• Mallards displayed a delayed margin of safety, increasing the risk of collisions at high speeds.
• The study suggests mallards are wholly unequipped to respond to vehicles at high speeds, with successful escapes occurring in less than 20% of approaches at the takeoff speed of aircraft (240 km/h).

The delayed margin of safety observed in mallards poses particular concern for airports and roads near water bodies where these birds frequently congregate. Despite efforts to reduce wildlife presence in these areas, complete separation is often impractical due to the birds’ adaptability to human environments.

"With mallards being active at night, particularly during migration, the risk of collisions is heightened, especially for aircraft. Most mallard strikes occur below 1,000 meters, suggesting that low-altitude flights during migration months pose the greatest danger.," 

Recommendations:

• Aircraft and vehicle operations should be minimized as much as practical during night hours and peak migration periods to reduce the risk of bird strikes.
• Future research should focus on enhancing the visual saliency of vehicles to birds, particularly at night, to allow for earlier detection and avoidance.

The research underscores the need for ongoing studies into avian avoidance behaviors and encourages the development of innovative solutions to improve safety for both humans and wildlife.