WASHINGTON — Billions fewer birds are flying through North American skies than decades ago, and their numbers are shrinking at an accelerating rate. This decline is largely attributed to the combined effects of intensive agriculture and warming temperatures, according to a fresh study.
Biggest Bird Losses in Areas Warming Most
The study, published Thursday in the journal Science, found that nearly half of the 261 species examined showed statistically significant losses. More than half of those in decline have experienced an acceleration of those losses since 1987. The research is the first to focus on the trends of bird decline – where losses are happening and what factors are connected – rather than simply total population numbers.
According to study co-author Marta Jarzyna, an ecologist at Ohio State University, “Not only are we losing birds, we are losing them faster and faster from year to year.” She noted that almost every group of birds is struggling, except for forest birds, prompting the question: “How do we protect these groups of birds?”
Farmland Issues Speed Up Bird Declines
The areas experiencing the most rapid acceleration of bird loss are the Mid-Atlantic, the Midwest, and California. While overall population declines are greater in the southern U.S., the rate of decline is linked to agricultural practices. Scientists found statistical correlations between accelerating decline and high fertilizer and pesticide use, as well as the amount of cropland.
Study lead author Francois Leroy, also an ecologist at Ohio State University, explained that “the stronger the agriculture, the faster we will lose birds.” Jarzyna added that agricultural intensification causes stronger accelerations of decline in regions where climate warming is most pronounced.
McGill University wildlife biologist David Bird, who was not involved in the study, noted that intensified agriculture leads to habitat conversion, nest destruction, and reduced food availability for birds, particularly due to a significant decline in insect populations – a crash of over 40 percent in many areas.
Birds Do a Lot for Humans
Researchers emphasize the significance of these losses. Richard Gregory, head of monitoring conservation science at University College London, described the study as “alarming” and “sobering.” Cornell University ornithologist Andrew Farnsworth, who wasn’t part of the study, stated that changes are needed to reduce human-caused warming and lessen the intensity of agricultural practices.
Frequently Asked Questions
What is driving the acceleration of bird loss?
The acceleration of bird loss is primarily driven by agricultural practices, particularly in regions experiencing the most significant warming temperatures, according to the study.
Are any bird species not experiencing decline?
Forest birds are the only group not showing significant declines, according to the study. Though, the species declining fastest – including the European starling, American crow, grackle, and house sparrow – are not currently at risk of extinction.
Why should we be concerned about declining bird populations?
Birds provide numerous benefits to humans, including pest control, pollination, and seed dispersal. Their presence also contributes to human well-being and happiness, and their decline may indicate broader environmental issues impacting all life, including humans.
Given these findings, what steps might communities and policymakers consider to mitigate the factors contributing to bird population decline?
