‘Bird Emergency:’ Big Population Declines In U.S., Including MD

The National Audubon Society has declared a “bird emergency” after a recent study found that the United States and Canada have lost a combined total of 2.9 billion birds since 1970 — a 29 percent decrease in the bird population over a 50-year period.

Just 12 bird families, including warblers, sparrows, blackbirds and finches, made up more than 90 percent of the total losses, according to the study published in “Science.” Additionally, birds that make grasslands their home had the largest population loss, with more than 700 million breeding birds across 31 different species disappearing over the course of the last five decades.

Not all bird populations are shrinking. For example, bluebirds are increasing, mostly because people have worked hard to get their numbers up.

Along with grasslands, bird loss in the United States was quantified in the study across three other terrains: western forest, aridlands and eastern forest. Maryland falls under eastern forest terrain in the study, where the bird population declined by 20 percent since 1970.

The study’s authors noted that the population loss was not restricted to rare or threatened bird species but includes many widespread and common species. These common birds, the authors write, may be disproportionately influential components of food webs and ecosystem function.

"We have seen these declines also in Maryland," Maryland Ornithological Society Conservation Chair Kurt Schwarz told Patch. There were nine species in particular within the forest interior dwelling species that experienced substantial losses, according to Schwarz.

"Cerulean Warbler was particularly acute, losing 73 percent, while Wood Thrush was down 60 percent, Veery by 40 percent," Shwarz said. "Grassland species suffered, too. American Kestrel is in steep decline, Northern Bobwhite even more so. Bobwhite have virtually disappeared in Montgomery, Howard, Baltimore, Carroll and Cecil Counties."

In an interview with the National Audubon Society, the study’s lead author, Ken Rosenberg, said that there wasn’t one factor accounting for the large losses of some birds.

“Multiple, complex environmental factors including pesticide use, insect declines, and climate change, as well as direct threats like outdoor cats and glass skyscrapers, are also hitting birds from a range of angles,” the Audubon Society wrote in its report on the study. “For migratory species, long journeys and changes to winter habitats could pose additional challenges.”

Since 2008, the group Lights Out Baltimore has found 4,000 birds that have died on Baltimore streets, mainly from crashing into glass windows. Lights Out Baltimore is a project of the Baltimore Bird Club that promotes turning off decorative lighting between 10 a.m. and 6 p.m. during peak migration season. Migration season can run from July to as late as December, according to the Maryland Ornithological Society.

In addition to encouraging people to turn off lighting, Lights Out Baltimore advocates for bird-friendly design practices. Birds can become disoriented by glass that is reflective or has no visual markers identifying it as someplace that is not safe to fly through, so people can add decals and remove vegetation from the area to make it more clear.

Another threat to birds are feline predators.

The Maryland Ornithological Society (MOS) in 2015 released a statement discouraging the free roaming of domestic cats and trap, neuter and release programs that promoted feral cat colonies.

"Recognizing that free-roaming and feral cats are probably the greatest source of human-caused bird mortality in North America, and constitute a major public and wildlife health threat, while at the same time being dangerous for the cats themselves, MOS discourages allowing domestic cats to wander freely in the landscape, and advocates keeping them indoors or confined in a way that they do not impact wildlife," MOS said in a statement.

In issuing its guidance, the organization cited local data from the Second Chance Wildlife Center in Gaithersburg that showed 80 percent of birds injured by cats between 2010 and 2013 did not survive. During that time, the wildlife center reportedly received nearly 500 birds of 41 species that were injured, meaning about 400 died.

To understand the change in the bird population, the study that "Science" released this month evaluated population change for 529 species in the continental U.S. and Canada or 76 percent of all breeding-bird species. In conclusion, the study’s authors wrote that the results show an urgent need to address the threats endangering birds.

“Since the 1970s, we’ve lost three billion of America’s birds. This is a full-blown crisis that requires political leadership as well as mass individual action. We have to act now to protect the places we know birds rely on. Places like the Arctic Refuge, Great Lakes, Everglades, and Colorado River must be a priority. From the newest Audubon members to the most tenured Senators, we all can act today to protect birds and the places they need," David Yarnold, president and CEO of the National Audubon Society, said in a statement.

“The connection between birds and humans is undeniable — we share the same fate,” Yarnold said. “This is a bird emergency with a clear message: the natural world humans depend on is being paved, logged, eroded and polluted. You don’t need to look hard for the metaphor: birds are the canaries in the coal mine that is the earth’s future."

— By Patch Editors Feroze Dhanoa and Elizabeth Janney. The Associated Press contributed to this report.

This article was updated Thursday, Sept. 26, to include comment from the Maryland Ornithological Society.