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Title: North America's Bird Populations Are Shrinking Faster. Blame Climate
Change and Agriculture

Link: https://news.slashdot.org/story/26/03/01/0332...

"Billions fewer birds are flying through North American skies than decades
ago," reports the Associated Press, "and their population is shrinking ever
faster, mostly due to a combination of intensive agriculture and warming
temperatures, a new study found." Nearly half of the 261 species studied
showed big enough losses in numbers to be statistically significant and more
than half of those declining are seeing their losses accelerate since 1987,
according to Thursday's journal Science... The only consolation is that the
birds that are shrinking in numbers the fastest are species - such as the
European starling, American crow, grackle and house sparrow - with large
enough populations that they aren't yet at risk of going extinct, said study
lead author Francois Leroy, also an Ohio State ecologist... When it came to
population declines - not the acceleration - the scientists noticed bigger
losses further south. When they did a deeper analysis they statistically
connected those losses to warmer temperatures from human-caused climate
change. "In regions where temperatures increase the most, we are seeing
strongest declines in populations," [said study co-author Marta Jarzyna, an
ecologist at Ohio State University]. "On the other hand, the acceleration of
those declines, that's mostly driven by agricultural practices." The
scientists found statistical correlations between speeded-up decline rates
and high fertilizer use, high pesticide use and amount of cropland, Leroy
said. He said they couldn't say any of those caused the acceleration of
losses, but it indicates agriculture in general is a factor. "The stronger
the agriculture, the faster we will lose birds," said Leroy... McGill
University wildlife biologist David Bird, who wasn't part of the study, said
it was done well and that its conclusions made sense. With a growing human
population, agriculture practices are intensified, more bird habitats are
being converted to cropland, modern machinery often grind up nests and eggs
and single crop plantings offer less possibilities for birds to find food and
nests, said Bird, the editor of Birds of Canada. "The biggest impact of
agricultural intensity though is our war on insects. Numerous recent studies
have shown that insect populations in many places throughout the world,
including the U.S., have crashed by well over 40 percent," Bird said in an
email. "Many of the birds in this new study showing population declines
depend heavily on insects for food." A 2019 study of the same bird species by
Cornell University conservation scientist Kenneth Rosenberg also found that
North America had 3 billion fewer birds than in 1970, the article points out.

Read more of this story at Slashdot.

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