Light Pollution Impacts on Seabird Populations

Artificial lighting along coastlines and on islands is reshaping nocturnal seascapes and disrupting critical life-history stages of seabirds. Nocturnally active groups such as petrels, shearwaters and storm-petrels are prone to disorientation and attraction by inappropriate wavelengths or excessive intensities, leading to mass grounding of fledglings and occasional avoidance of essential feeding corridors by adults. Such disturbances cause direct mortality, reduced breeding success and cascading demographic declines. Beyond fatalities, sub-lethal effects on stress physiology, predation risk and energy expenditure further undermine population resilience. Given seabirds’ pivotal roles in nutrient transport and marine trophic dynamics, light pollution poses a threat not only to individual species but also to broader ecosystem functioning. Recent work has defined species-specific responses to light colour and duration, mapped spatial thresholds for safe passage to sea, and linked visual system development to vulnerability. These insights underpin practical mitigation measures—spectral adjustment of lighting, shielded fixtures and establishment of dark refuges—to conserve seabird populations at a global scale.

Research from Nature Portfolio

Experimental trials adjacent to breeding colonies have demonstrated that adult Manx shearwaters are repelled more strongly by green and blue light than by red light, with higher intensities and longer illumination periods exacerbating flight avoidance. These findings validate the use of low-intensity red lighting and limited on-time schedules to reduce disturbance at nesting sites. In parallel, GPS tracking combined with high-resolution satellite night-time imagery has quantified the radiance thresholds above which Cory’s shearwater fledglings become grounded. This work revealed that most grounding incidents occur within a few kilometres of colonies where light radiance exceeds critical values, and it established the required spatial extent of dark refuges to enable safe nocturnal flights towards the ocean.

Light Pollution Impacts on Seabird Populations publication trend

The graph below shows the total number of articles in light pollution impacts on seabird populations across all publications each year (not limited to Nature Index journals).

Technical terms

Light pollution: the introduction of artificial light into natural environments, disrupting normal patterns of darkness.

Grounding: the phenomenon whereby seabirds disoriented by artificial light land on land instead of reaching the sea.

Radiance: the amount of light energy emitted or reflected from a surface per unit area in a specified direction.

Dark refuge: an area with minimal artificial illumination that provides safe nocturnal passage for seabirds.

Flight tortuosity: a measure of deviations from a straight path, indicating disoriented or circuitous flight behaviour.

References

1. Avoidance of different durations, colours and intensities of artificial light by adult seabirds. Scientific Reports (2021).
2. GPS tracking for mapping seabird mortality induced by light pollution. Scientific Reports (2015).
3. Is seabird light‐induced mortality explained by the visual system development?. Conservation Science and Practice (2020).
4. Effects of land-based light pollution on two species of burrow-nesting seabirds in Newfoundland and Labrador, Canada. Avian Conservation and Ecology (2021).
5. Post-release survival of fallout Newell’s shearwater fledglings from a rescue and rehabilitation program on Kaua‘i, Hawai‘i. Endangered Species Research (2020).
6. Tracking Flights to Investigate Seabird Mortality Induced by Artificial Lights. Frontiers in Ecology and Evolution (2022).