Relevance: GS III (Environment, Biodiversity & Climate Change) | Source: The Hindu

1. The Big Discovery

• The Old Belief: For decades, scientists believed that mountain birds migrated up and down (elevational migration) purely to escape extreme hot or cold temperatures.
• The New Truth: A new global study has proven this wrong. Birds actually migrate vertically to optimize their “Energy Budget”. This means they move up or down specifically to find abundant food (like insects or fruits) and escape competition, not just to find a comfortable climate.

2. The Indian Context 

• Research conducted by the Indian Institute of Science (IISc), Bengaluru, confirmed this pattern in the Himalayas.
• They found that insect-eating birds move down to the valleys in winter and up the mountains in summer strictly because they are following the seasonal movement of flying insects. They are tracking food, not the thermometer.

3. The Climate Threat: The “Squeeze Effect”

• As global warming heats the planet, plants and insects are shifting higher up the mountains.
• Consequently, birds are forced to follow their food higher (projected to shift 129 meters upslope by 2100). Eventually, as they keep moving up, they will “run out of mountain” and face local extinction.

4. The Power of Citizen Science

• This massive discovery was made possible by eBird, a global citizen science database where ordinary birdwatchers log their sightings. This proves that public participation is becoming crucial for global conservation policies.

UPSC Value Box

With reference to avian migration and global conservation frameworks, consider the following statements:

1. Recent scientific models suggest that the elevational migration of mountain birds is primarily driven by the need to optimize energy budgets rather than solely tracking temperature changes.
2. The eBird database, widely utilized for global avian research, is a statutory database maintained by the Zoological Survey of India (ZSI).
3. The Convention on Migratory Species (CMS), also known as the Bonn Convention, operates under the aegis of the United Nations Environment Programme (UNEP).

Which of the statements given above is/are correct?

(a) 1 and 2 only

(b) 1 and 3 only

(c) 3 only

(d) 1, 2 and 3

Correct Answer: (b)