Light tuned to the avian eye elicits early detection and escape from an approaching aircraft.

Collisions between birds and aircraft are a global problem. We identified different behavioural parameters affecting the probability of escape from a potential collision with an approaching aircraft, which is a function of the probability that the animal initiates an escape response (probability of reaction) and the probability of having enough time to escape (probability of sufficient time). Lights of high chromatic contrast tuned to the avian eye have been proposed as a solution to mitigate collisions. We approached Canada geese with a drone to estimate how aircraft lighting and changes in altitude, mimicking the flight phase where most strikes occur, affect parameters associated with the probability of escape. Onboard lights increased parameters associated with the probability of reaction at farther distances by promoting longer detection distances, which enabled the animal to initiate each stage of its escape response sooner leading to longer flight-initiation distances irrespective of altitude changes. Additionally, onboard lights increased parameters associated with the probability of sufficient time where longer detection distances allowed animals to escape away from (as opposed to towards) the approaching drone. Our findings have implications for the development of light technology to deter birds away from approaching vehicles, and other anthropogenic structures (such as wind turbines and solar facilities).