High-intensity urban light installation dramatically alters nocturnal bird migration

Area of Science:

• Ornithology
• Environmental Science
• Urban Ecology

Background:

• Billions of birds migrate nocturnally, relying on natural cues disrupted by artificial light at night (ALAN).
• Previous research lacked quantification of avian responses to intense urban light sources.

Purpose of the Study:

• To quantify the behavioral effects of a powerful urban light installation on nocturnally migrating birds.
• To model bird disorientation and attraction in response to artificial light at night (ALAN).

Main Methods:

• Monitoring the "Tribute in Light" installation in New York using radar and acoustic sensors.
• Quantifying bird behavior, including aggregation, flight speed, and vocalization.
• Simulating bird disorientation and attraction probabilities.

Main Results:

• A single light source altered bird behavior up to 4 km altitude, influencing an estimated 1.1 million birds.
• Birds exhibited increased density (20x baseline), decreased speed, circular flight paths, and vocalizations when lights were on.
• Behavioral disruptions ceased when lights were extinguished.

Conclusions:

• Selective light removal during migration is a viable strategy to mitigate ALAN impacts on birds.
• Urban light installations pose significant risks to migrating birds, necessitating further research and conservation strategies.