What Are The Specific Spectral Characteristics Of LED-based Coastal Development Lighting That Are Most Likely To Disrupt The Migratory Stopover Behavior Of Juvenile Semipalmated Sandpipers During Their Nocturnal Foraging Periods, And How Can These Effects Be Mitigated Through The Use Of Alternative Lighting Technologies Or Clever Beam-shaping Designs?

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The disruption of migratory stopover behavior in juvenile Semipalmated Sandpipers by LED coastal lighting can be attributed to several spectral and temporal factors, which can be mitigated through thoughtful lighting strategies:

Spectral Characteristics Causing Disruption:

  1. Blue Light Emission: LEDs, particularly cool white ones, emit significant blue light (400-500 nm), which can interfere with birds' navigation and foraging behaviors, as birds are more sensitive to these wavelengths.

  2. Intensity: High-intensity lighting can disrupt nocturnal behaviors, affecting the birds' ability to forage and navigate effectively.

  3. Polarization: Highly polarized light from LEDs may interfere with birds' ability to use polarized light cues for orientation, potentially disorienting them.

Mitigation Strategies:

  1. Alternative Lighting Technologies:

    • Warmer LEDs: Use LEDs with warmer color temperatures (2700K-3000K) that emit less blue light, reducing disruption.
    • Smart Lighting: Implement systems that adjust color temperature and intensity based on time, using warmer tones during migration periods.

  2. Beam-Shaping Designs:

    • Full Cutoff Fixtures: Direct light downward to minimize glare and light trespass, reducing impact on bird habitats.
    • Shielding and Lenses: Focus light where needed, avoiding unnecessary spread that might attract or disorient birds.

  3. Temporal Adjustments:

    • Dimming and Timers: Dim lights during peak migration times and use timers to limit operation to necessary periods.
    • Motion Sensors: Activate lights only when needed to reduce continuous illumination.

  4. Broader Planning:

    • Wildlife-Friendly Planning: Locate lights away from critical habitats and consider light-free zones near areas frequented by birds.
    • Intensity Thresholds: Keep lighting below disruption levels, informed by research on bird sensitivities.

By addressing these factors, coastal development can reduce the impact on migratory birds while maintaining necessary lighting for human activities.