Overall, urban and suburban bird populations have increased relative to their late 1960s levels , with notable increases during the 1990s and 2000s (Exhibit 2). The BBS produces an index of relative abundance rather than a complete count of breeding bird populations.
The first-ever comprehensive assessment of net population changes in the U.S. and Canada reveals across-the-board declines that scientists call “staggering.” All told, the North American bird population is down by 2.9 billion breeding adults, with devastating losses among birds in every biome.
But while the results are troubling, there is some good news. Not all birds declined and some species even showed steady gains over time . Waterfowl as a group, for example, saw a population increase of 34 million individuals since 1970, thanks largely to wetland conservation efforts.
Trends in bird populations and in the abundance of different bird species are influenced by changes in landscape and habitat , the availability and quality of food, toxic chemicals, and climate.
New research estimates there are between 50 billion and 430 billion birds on Earth.
Hundreds of bird species in India are in decline , according to the country's first major report on the state of bird populations. Birds of prey and waterbirds seem to have been hit particularly hard owing to habitat destruction, hunting and the pet trade. But it's not all bad new
The biodiversity crisis has come to our backyards. In less than a single human lifetime, 2.9 billion breeding adult birds have been lost from the United States and Canada , across every ecosystem and including familiar birds: The Dark-eyed Junco has lost an incredible 175 million individuals from its population.
Since the 1500s, birds have been declining both in terms of species numbers (by about 500 species) and numbers of individuals (by about 20-25%). This decline is due to human activities, such as the cutting down of forests, contamination, invasive species , and human-induced climate change .
Birds that nest in tree canopies such as cormorants, painted stork, brahminy kite, and egrets are increasing. The study observed that this might be because of the availability of nesting sites in the islands created by the authorities. ... Fish-eating birds such as cormorants, oriental darter are increasing in the city.
Researchers at Cornell's Lab of Ornithology and Canada's National Wildlife Research Centre found in a 2019 analysis that wild bird populations in the continental U.S. and Canada have declined by 29 percent —or a total net loss of around three billion birds—since 1970.