Artificial Light at Night and Wildlife Welfare

Artificial light at night (ALAN) disrupts the biological rhythms of a vast range of wildlife, with welfare consequences that are only beginning to be understood at full scale.

Key Facts

Global light pollution has increased by approximately 2% annually over the past 25 years
Artificial light at night disrupts circadian rhythms in mammals, birds, fish, invertebrates, and plants
Sea turtle hatchlings are disoriented by coastal light pollution, leading them away from the ocean
Migrating birds in millions collide annually with illuminated buildings, with collisions highest during cloudy nights
Insects attracted to artificial lights experience exhaustion, predation, and reproductive failure

Welfare Considerations

Artificial light at night represents one of the most pervasive and under-recognised welfare threats to wild animals globally. The disruption of circadian rhythms affects sleep, immune function, hormone regulation, and behaviour in ways that cause chronic welfare compromise across many taxonomic groups. For individual animals, light pollution causes disorientation, altered predator-prey dynamics, changed feeding times, and reproductive failures. At population scale, light pollution is implicated in insect declines, bird collision mortality, and sea turtle nesting failure. Mitigation requires both individual action through garden lighting choices and systemic changes to urban and industrial lighting standards.

What You Can Do

Use warm-spectrum, downward-directed outdoor lighting to reduce impact on wildlife
Install motion sensors on outdoor lights so they illuminate only when needed
Participate in citizen science projects monitoring bird-building collisions in your city
Support campaigns for wildlife-friendly lighting standards in urban planning and building regulations
Advocate for designated dark sky areas near ecologically sensitive habitats