Bird Census Highlights Changes at Chilika Lake

Chilika Lake, Asia’s largest brackish water lagoon, has seen a decrease in bird visitors this winter. The annual bird census, conducted on January 18, 2025, recorded 1,127,228 birds of 196 species. This number is lower than the previous year’s count of 1,137,759 birds. However, the survey noted an increase in the variety of species visiting the lake.

Key Findings from the Census

The census reported 1,087,226 migratory birds from 109 species. In contrast, resident birds numbered 40,002 from 87 species. The previous year had recorded 1,098,813 migratory birds from 108 species and 38,946 resident birds from 79 species. This indicates a slight decline in overall bird numbers but a positive trend in species diversity.

Comparative Analysis of Bird Populations

In 2023, the census recorded 1,131,929 birds of 184 species. The increase in species diversity is noteworthy. The Hirakud wetland and Bhitarkanika National Park reported rising bird populations this year. Hirakud hosted 377,732 birds from 122 species, up from 342,345 birds of 113 species in 2024. Bhitarkanika recorded 151,614 birds from 118 species, slightly up from 151,421 birds of 121 species last winter.

Factors Influencing Bird Counts

The decrease in bird numbers at Chilika Lake is attributed to higher water levels caused by unexpected rains in December 2024. This change reduced the availability of mudflats, critical for waterfowl feeding. Many migratory birds may have shifted to nearby farmlands and wetlands with more abundant food resources. Experts view this decline as a natural phenomenon.

Species Highlights

The census revealed that Gadwalls were the most numerous, with a count of 201,926. Northern Pintails followed closely with 193,394, and Eurasian Wigeons numbered 154,937. Notably, Greater Flamingos saw an increase from 820 last year to 2,638 this winter. This indicates a positive trend for certain species amidst overall declines.

Collaboration and Methodology

The bird census was a collaborative effort involving the Chilika wildlife division and the Chilika Development Authority. Technical support came from the Bombay Natural History Society. A total of 126 experts, including researchers and wildlife activists, participated in the survey. Their collective efforts contribute to understanding avian populations in the region.

Importance of Chilika Lake

Chilika Lake serves as important wintering ground for migratory birds from various regions, including Northern Eurasia and Siberia. These birds migrate to escape harsh winters and begin their journey home before summer. The lake’s ecological significance cannot be overstated, as it supports diverse wildlife and contributes to biodiversity.

Questions for UPSC:

1. Examine the impact of climate change on migratory bird patterns in India.
2. Critically discuss the ecological significance of Ramsar sites in India.
3. Analyse the role of wetlands in supporting biodiversity and combating climate change.
4. Estimate the effects of human activities on the migratory routes of birds in South Asia.

Answer Hints:

1. Examine the impact of climate change on migratory bird patterns in India.

1. Climate change alters temperature and precipitation patterns, affecting migration timing.
2. Changes in habitat availability due to rising sea levels can disrupt traditional migratory routes.
3. Increased frequency of extreme weather events can lead to habitat loss and food scarcity.
4. Shifts in food availability along migration routes can affect survival and reproduction rates.
5. Research indicates that some species are adapting by altering migration strategies, while others face population declines.

2. Critically discuss the ecological significance of Ramsar sites in India.

1. Ramsar sites are critical for biodiversity, supporting numerous species of flora and fauna.
2. They provide essential ecosystem services such as water purification, flood control, and carbon sequestration.
3. These wetlands serve as vital habitats for migratory birds, enhancing global biodiversity.
4. Conservation of Ramsar sites helps mitigate the impacts of climate change by preserving natural buffers.
5. They also support local economies through fishing, tourism, and agriculture, promoting sustainable livelihoods.

3. Analyse the role of wetlands in supporting biodiversity and combating climate change.

1. Wetlands provide critical habitats for diverse species, including endangered and migratory birds.
2. They act as carbon sinks, absorbing and storing carbon dioxide from the atmosphere.
3. Wetlands enhance water quality by filtering pollutants and improving nutrient cycling.
4. They help in flood regulation and groundwater recharge, contributing to ecosystem resilience.
5. Conservation of wetlands is essential for sustaining biodiversity and enhancing climate adaptation strategies.

4. Estimate the effects of human activities on the migratory routes of birds in South Asia.

1. Urbanization and land-use changes lead to habitat fragmentation, disrupting migratory pathways.
2. Pollution from agriculture and industry can degrade habitats and reduce food availability.
3. Infrastructure development, such as roads and dams, can create barriers to migration.
4. Climate change, driven by human activities, alters weather patterns and affects migration timing.
5. Conservation efforts are needed to mitigate these impacts and ensure safe migratory routes for birds.