Bird populations are declining worldwide

A new study led by Bird Ecology and Conservation Ontario (BECO) – a non-profit organization that uses ecological research to advance the conservation of birds – has found that 47 percent of bird species with currently unknown population trends are declining. Globally, the top predictor associated with bird declines was a severely fragmented population, with non-migratory birds in South American and Southeast Asian tropical and subtropical forests being the most vulnerable.

“Birds are crucial for the functioning of Earth’s ecosystems but bird population declines have been documented worldwide in recent decades. A global assessment of potential causes of population declines is needed,” wrote the study authors. 

“Our goal here was to combine the power of big data and machine learning to identify predictors correlated with bird population declines and to predict population declines for species with unknown population trends on the IUCN Red List.”

Initially, in order to train and test the machine learning model that they had constructed, the researchers gathered detailed species-level data for 10,964 bird species from all around the globe with known population trends. Then, they used this artificial intelligence model to analyze 801 bird species with previously unknown population trends. The model estimated that almost half (47 percent) of these species are currently declining.

According to the researchers, the main causes of decline are habitat loss and fragmentation. “Populations experiencing habitat fragmentation are subject to greater demographic, environmental and genetic stochasticity, and hence higher extinction risk,” wrote the study authors.

“Previous studies have suggested that habitat loss and fragmentation are major drivers of bird population declines. Our results support this hypothesis, as severely fragmented populations emerged as the top predictor explaining bird population declines worldwide,” wrote the study authors.”

Since birds play important ecological roles such as pollination, seed dispersal, and nutrient cycling, their marked decline could have severe cascading impacts on a variety of ecosystems worldwide, and needs immediate attention from conservationists and policy makers. 

The study is published in the journal Ibis.

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By Andrei Ionescu, Earth.com Staff Writer