Land Stewardship
Dark sky lighting and why it matters for backyard wildlife
May 3, 2025 · 5 min read
Artificial light at night — ALAN, in the literature — is one of the fastest-growing forms of environmental degradation, and its effects on wildlife are only now being fully catalogued. Adjusting your outdoor lighting is one of the cheapest and most immediate stewardship actions available.
The scope of the problem
Global light pollution has been growing by roughly 2 to 10 percent per year depending on the region. Effects are documented across insects (attraction, exhaustion, predation), birds (disorientation during migration, altered dawn chorus timing), amphibians (suppressed foraging), mammals (shifted activity), and plants (altered flowering).
The five dark-sky principles
Only when useful. Only where needed. Only as much as necessary. Shielded so light points down, not sideways or up. Warm color temperatures — under 3000K, ideally under 2200K — because short-wavelength blue light has the highest ecological impact.
Practical retrofits
Replace unshielded floodlights with downward-shielded fixtures. Replace 5000K white LEDs with 2700K or warmer. Add motion sensors so lights are off when nothing is there. Time landscape lighting to shut off at 10 or 11 PM rather than dusk-to-dawn.
Wildlife responses
Reductions in outdoor lighting typically produce measurable rebounds in local moth abundance within weeks, and in bat foraging within a season. If your yard has fallen quiet at night, unshielded lighting may be part of the reason.