Artificial Light at Night and Wildlife Welfare

Light pollution from human settlements disrupts the behaviour, physiology, and ecology of nocturnal and crepuscular wildlife species.

Key Facts

Light pollution has increased globally at approximately 6% per year over the past decade
Nocturnal insects are disoriented by artificial lights, increasing predation and disrupting pollination
Sea turtle hatchlings navigate to the sea using natural light gradients and are confused by beach lighting
Migratory birds use star patterns for navigation and can be disoriented by lit buildings during migration
Artificial light suppresses melatonin production in many mammals, disrupting sleep and reproductive cycles
Dark sky reserves and lighting ordinances can measurably reduce light pollution impacts
LED street lights that emit blue-spectrum light have more severe effects on wildlife than warm-toned alternatives

Welfare Considerations

Artificial light at night (ALAN) represents one of the most pervasive and underappreciated forms of human impact on wildlife welfare. For nocturnal species that evolved in darkness, consistent exposure to artificial light disrupts fundamental biological rhythms including sleep, hormone production, and reproductive timing. Individual welfare harms include chronic sleep disruption, altered foraging and predator avoidance behaviour, and reproductive dysfunction. At the population level, light pollution disrupts migratory navigation causing disorientation and mortality, suppresses insect populations that form the foundation of many food webs, and shifts the competitive balance between light-tolerant and light-sensitive species. Solutions exist at individual, community, and policy levels and represent a relatively tractable environmental welfare challenge.

What You Can Do

Use motion-sensitive, directional, and warm-spectrum outdoor lighting at your home
Support dark sky initiatives and lighting ordinances in your community
Turn off unnecessary indoor lights at night during migratory bird seasons
Advocate for wildlife-sensitive lighting guidelines in planning and development decisions
Support research into the ecological and welfare impacts of light pollution on wildlife