The skies over North America are witnessing a dramatic decline in bird populations, a recent study has uncovered. The research attributes this worrisome trend to intensive agricultural activities and rising temperatures, painting a stark picture of the challenges facing avian species today.
A significant portion of the 261 bird species analyzed in the study experienced notable population decreases, with nearly half showing statistically significant losses. More troubling is that over half of these declining species are losing numbers at an accelerating rate since 1987, according to findings published in the journal Science.
This research marks the first attempt to delve deeper than overall bird population figures, by assessing the specifics of their decline, including regional trends and contributory factors. “Not only are we losing birds, we are losing them faster and faster from year to year,” commented Marta Jarzyna, an ecologist at Ohio State University and co-author of the study.
Are shrinking bird species at risk of extinction?
There is some relief in knowing that the species experiencing the most rapid decline, including the European starling, American crow, grackle, and house sparrow, still have large enough populations to avoid immediate extinction risk, according to Francois Leroy, the study’s lead author and an ecologist at Ohio State University.
Kenneth Rosenberg, a conservation scientist at Cornell University who was not involved in the study, pointed out that these declining species are often viewed as “pests or ‘trash birds’.” He noted, “If our environment cannot support healthy populations of these extreme generalists and extremely adaptable species that are tolerant of humans, then that is a very strong indicator that the environment is also toxic to humans and all other life.”
Where are birds declining fastest?
The study identified the Mid-Atlantic, Midwest, and California as regions with the most significant acceleration in bird loss. In contrast, population declines, not necessarily the acceleration, were more pronounced in southern areas such as Florida and Texas, where they were linked to warmer temperatures driven by human-caused climate change.
“In regions where temperatures increase the most, we are seeing strongest declines in populations,” explained Jarzyna. “On the other hand, the acceleration of those declines, that’s mostly driven by agricultural practices.”
The researchers observed statistical connections between faster decline rates and factors like high fertilizer and pesticide use, along with extensive cropland. While these findings do not establish causation, they suggest agriculture plays a significant role, according to Leroy.
Why are birds important?
Birds are crucial to maintaining healthy ecosystems. Jarzyna emphasized their roles, stating, “We see birds being good pollinators. We see them dispersing seeds, we see them as pest control, they play really important functions. And if they disappear, those functions are gone as well. So from the perspective of ecosystem functioning, it’s really important that our birds don’t go away.”
The widespread destruction of habitats is a growing concern. Jarzyna highlighted the challenge, noting, “Basically every single habitat type, so species that breed in things like grasslands or deserts or marshes and so on, is declining with exception of forests, of forest birds. So we need to ask ourselves a question. How do we protect these groups of birds?”
Original Story at www.euronews.com