The windshield phenomenon (or windscreen phenomenon) is the observation that recently fewer dead insects accumulate on the windshields of people's cars. It has been attributed to a global decline in insect populations caused by human activity.
A 20-year study measured the number of dead insects on car windscreens on two stretches of road in Denmark from 1997 until 2017. Adjusted for variables such a time of day, date, temperature, and wind speed, the research found an 80% decline in insects. A parallel study using sweep nets and sticky plates in the same area positively correlated with the reduction of insects killed by car windscreens.