How birders help conservation

Crowdsourced bird information is a valuable resource. But relying solely on this data might lead to flawed conclusions, writes Rupsy Khurana

As we transition to winter, bird enthusiasts gear up to welcome the avian globetrotters like European rollers and grey wagtails, reaching our land in huge numbers. And birdwatchers are using an online database, eBird, to document detailed notes on the birds seen or heard, their behaviour, habitat, songs and much more.

Scientists around the world are using crowdsourced information to investigate the threats of deforestation, agricultural expansion, light pollution, and climate change, and their impact on the long-term survival of birds.

India is one of the largest contributors to eBird database amongst tropical countries.

“eBird as a tool fascinates people as it helps maintain one’s birding experience. Friendly challenges run by other citizen science portals connect people with birds and nature while also spreading awareness about the multitudes of threats birds face,” says Praveen J, scientist, Bird Count India.

Birds and climate change

In a recent study, Vijay Ramesh, a research scholar at the University of Columbia, compiled about 1.29 million observations from eBird recorded between 2013 to 2021. Vijay and his team used observations of 79 species found in the Nilgiri and Anaimalai hills of the Western Ghats to predict if environmental changes can drive the distribution of birds in a landscape.

“We have used these observations to understand how the presence or absence of various species might be influenced by changing climate and transformation of landscapes in future”, says Vijay.

The Nilgiri and Anaimalai hills harbour various habitats ranging from evergreen forests to grasslands. In this study, researchers categorised resident and migratory birds of the Western Ghats as forest species and generalist species.

Forest species are found in wet, naturally-occurring habitats of evergreen and deciduous forests. However, the generalist species are associated with agriculture, human settlements and plantations.

The team used public data to examine how likely it was for a species to adapt to the plausible changes in temperature and rainfall, and modification of natural landscapes.

They rigorousy filtered data to remove checklists submitted during the rains and low-light conditions, sightings of birds like raptors, swifts and swallows which are mostly observed in flight and many other checklists which were prone to misidentification of species by amateur or even experienced birders.

As per their assumptions, ornithologists found that forest species such as the crimson-backed sunbird and chestnut-headed bee-eater would be negatively affected by temperature fluctuations that we currently witness. “In the future, one could expect that increasing temperatures will only continue to have a negative effect on forest bird species. We found naturally occurring land cover types like forests are crucial for the long-term persistence of specialist species,” says Vijay.

Other studies conducted in tropical mountains have suggested that specialist birds occupying habitats at certain elevations are adapted to a narrow range of temperatures. Temperature fluctuation might make the habitat unsuitable for such species. However, increase in rainfall might benefit forest species like southern hill myna and crimson-backed sunbird, as it increases the availability of food.

In line with the expectations of the research team, generalist species such as spotted dove and purple sunbird adapt well to a broad range of temperatures.

Though the researchers did not examine the declines in the bird numbers, Vijay explains, “Changes in the species community, for example, more generalist species and fewer forest species in a particular area can have cascading effects on natural systems. Losing a forest species that aids in seed dispersal can have a negative impact on plant species and thereby lead to disruptions in ecosystem functioning.”

Citizen science

The eyes and ears of birdwatchers have helped scientists design effective conservation strategies. “In 2020, 10 research and conservation organisations in India came together to create a State of India's Birds, an evaluation of conservation concerns of regularly occurring species. The report used eBird data and evaluated 101 species as High Conservation Concern,” informs Praveen.

Citizen science has the potential to supplement scientific efforts and plug information gaps but it is not without challenges.

Vijay says, “Citizen science data is not always complete. Even within the Nilgiris or the Anaimalais, most eBird observations were reported within 300 m of a road, which means that our data is restricted to areas accessible to birdwatchers. So if rigorous filtering and examining eBird data is not carried out, the results are not inherently accurate. However, combining citizen science data and detailed surveys can address the challenge.”

Priyamvada Bagaria, a consultant at the Ministry of Environment, Forest and Climate Change, echoes similar concerns. “Though citizen science platforms like eBird, and Global Biodiversity Information Facility are useful resources, they must be used with utmost care in scientific research. One needs to spend a good deal of time cleaning up the data for outliers, erroneous locations, or any suspected ambiguity.”

Challenges

Proponents of citizen science are often met with arguments that the data is not collected systematically as it would be in a scientifically designed data collection strategy. “Citizen science information, when collected without planning for a specific question, is good enough to understand volunteer motivations and efforts but to presume that it reflects activities or behaviour of certain species is incorrect. Equating unplanned volunteer observations with scientific data is a problem”, says Gopi Sundar, Co-chair, the International Union for Conservation of Nature Stork, Ibis and Spoonbill Specialist Group.

“eBird or other such platforms are good to look for patterns as a preliminary step to help develop interesting questions for study. However, before stating that those patterns and associations are true, they would need to be compared with data developed using a systematic scientific study,” he adds.

Additionally, many studies only use checklists wherein a species is present and seldom consider checklists where that species is absent.

Gopi suggests that using unplanned volunteer observations as data without carefully considering biases in scientific analysis, especially to assess species abundance or density, can lead to an understanding of species biology with unknown errors and even flawed conservation policies.