Environment and Ecology, Science and Technology, Biodiversity, Current Affairs, and Animal Behavior.

What the studies are showing

• By analysing millions of bird sound recordings from hundreds of species, scientists found that artificial light at night shifts daily routines.
  
• Birds with larger eyes (more sensitive to low light) showed the biggest shift in timings; small-eyed species changed little.
  
• The change is sharpest in the breeding season when birds sing, court, defend territory, and feed chicks.
  

Why this matters

• Body clock disruption: Night lighting suppresses melatonin, weakens sleep, and shifts the dawn chorus and feeding times.
  
• Breeding and survival: Earlier or longer activity can mismatch food availability for chicks; tired adults may face higher predation.
  
• Migration and collisions: Lit skylines and skyglow draw migrants off course, causing window strikes and energy loss.
  
• Ecosystem ripple: If insect-eating birds feed at different hours, pest control and pollination patterns may change.
  

India angle

• Rapid urbanisation means more lit roads, buildings, and industrial sites, often near wetlands and flyways used by migrants.
• City “skyglow” is noticeable even in smaller towns; protected areas near cities can be affected.

What can be done 

• Design lights wisely: Use fully shielded fixtures that point light down; choose warm colour lamps (below 3000 Kelvin).
• Dim and time: Motion sensors, curfews after midnight, and lower brightness for empty spaces.
• Make buildings bird-safe: Turn off decorative lighting during peak migration; use patterned glass or external screens.
• Plan at city scale: Include “dark corridors” along rivers, wetlands, and tree belts in master plans; monitor light levels as an urban metric.

Prelims practice

Q. Consider the following statements about the impact of artificial light at night on birds:

1. Birds with larger eyes tend to show stronger timing shifts than small-eyed species.
2. The effect is usually weakest during the breeding season.
3. Shielded, warm-colour streetlights reduce skyglow and help birds.

Which of the statements is/are correct?
A. 1 and 3 only
B. 2 only
C. 1 and 2 only
D. 1, 2 and 3

Answer: A