The global population of Eastern Meadowlarks has declined by 75 percent since 1970. And the future looks worse. According to a new report, North America stands to lose half of what’s left of meadowlarks before the year 2040.
“Half-lives” is the morbid new metric debuted in a report released by Partners in Flight, a supergroup of 150 bird conservation nonprofits and government agencies throughout the Western Hemisphere.
Coming on the heels of a State of North America’s Birds report that calculated more than a third of the continent’s bird species were in need of urgent conservation action, the half-lives statistic is yet another attempt by ornithologists to quantify and communicate to the public about the ongoing, tremendous loss of birdlife.
Since 1970, a suite of 46 landbird species have lost more than 1.5 billion breeding individuals in their total continental population—a staggering decline that, according to the report, “could disrupt the structure and function of ecosystems.”
For this report, scientists calculated the half-life of declining species by estimating the number of years before an additional 50 percent of their global population is lost, if current trends continue. More than a dozen species had half-lives of fewer than 34 years, meaning they would lose half their remnant populations by 2050.
“The half-life metric conveys a sense of urgency. How long before the abundance of birds that we all enjoy will be cut in half?” says Bob Ford, the Partners in Flight national coordinator. “When most of us see those numbers, we want to change them.”
Cornell Lab conservation scientist Ken Rosenberg, a lead author on the report, adds that the half-life calculations surprised even him.
“The window for reversing declines and preventing extinctions is narrower than we thought,” Rosenberg says.