Future looms dark for 48% of bird species

The State of the World’s Birds says 13.5% of 10,994 recognised extant species are currently threatened with extinction

GUWAHATIHumans eat 14% of the world’s surviving species of birds. However, this is not the only reason why 48% of the extant bird species are undergoing population decline, a study by nine renowned avian experts and conservationists has revealed.

The State of the World’s Birds, an annual review of environmental resources published on May 5, has attributed the threat to almost half of the 10,994 recognised extant species of birds to the expanding human footprint on the natural world and climate change.

The degradation and loss of natural habitats as well as direct overexploitation of many species are the key threats to avian biodiversity, the study led by the Manchester Metropolitan University (MMU) says.

The use of 37% of the surviving bird species as common or exotic pets and 14% as food are examples of direct overexploitation, the report indicates.

The review found that 5,245 or about 48% of the existing bird species worldwide were known or suspected to be undergoing population decline. While 4,295 or 39% of the species had stable trends, about 7% or 778 species had increasing population trends. The trend of 37 species was unknown.

The study underlines birdwatching, a global pastime involving millions of people, as a form of avian conservation but warns of “local negative impacts” of bird feeding valued at $5-6 billion per year and growing by 4% annually.

The caution is for some non-provisioned species via trophic cascades, an “ecological phenomenon triggered by the addition or removal of top predators and involving reciprocal changes in the relative populations of predator and prey through a food chain, which often results in dramatic changes in ecosystem structure and nutrient cycling”.