US bird populations are experiencing alarming declines due to factors such as habitat loss and climate change, according to a new report identifying 112 species that have reached a “tipping point,” including 42 with perilously low numbers and steep downward trends.
Even duck populations, which have been considered a conservation success story, have trended downward in recent years, though they are still higher than 1970 levels, according to the report, released on Thursday by a group of science and conservation organisations.
The report looked at 718 species using population data such as the Cornell Lab of Ornithology’s eBird Status and Trends project, the US Geological Survey’s Breeding Bird Survey and National Audubon Society avian counts.
“Roughly one in three bird species (229 species) in the US requires urgent conservation attention, and these species represent the major habitats and systems in the US and include species that we’ve long considered to be common and abundant,” said Amanda Rodewald, faculty director of the Cornell Lab of Ornithology’s Center for Avian Population Studies.
The report identified species that have reached a “tipping point,” having lost more than 50% of their numbers within the past half-century. Among those, it listed 33 “yellow alert” species with long-term population losses but relatively stable recent trends, 37 “orange alert” species with long-term losses that accelerated within the past decade and 42 “red alert” species with dangerously low numbers and precipitous declines.
Some of these red alert species included the mottled duck, Allen’s hummingbird, yellow-billed loon, red-faced cormorant, greater sage-grouse, Florida scrub jay, Baird’s sparrow, saltmarsh sparrow, mountain plover, Hawaiian petrel, Bicknell’s thrush, Cassia crossbill, pink-footed shearwater, tricolored blackbird and golden-cheeked warbler.
Some of these birds already have protections under the US Endangered Species Act.
“Habitat loss and degradation remain the most important contributors to declines of birds and other species,” Rodewald said.
Other factors cited in population declines included climate change, invasive species, pollution, and bird collisions, for instance with wind turbine blades and buildings.
The report found that avian populations are decreasing in almost every habitat, including grasslands and arid regions. Shorebirds are the group with the most “tipping point” species, at 19.
“It represents a huge biodiversity loss,” said Michael Parr, president of the American Bird Conservancy.
“The only bright spot is water birds such as herons and egrets that show some increases,” Parr added.
Some examples of common birds now in decline include the chimney swift, wood thrush, grasshopper sparrow, eastern meadowlark, common grackle, barn swallow, blackpoll warbler, herring gull and bobolink.
“We have brought bird populations back from the brink before and we can do it again,” said Marshall Johnson, the National Audubon Society’s chief conservation officer, pointing to the bald eagle as an example of conservation success.
“Not only do birds play an important role in our ecosystems, they’re also incredibly important parts of our lives,” he said. “Protecting birds is good for the environment, local economies, and it’s good for people.”
