North America's Bird
Population Has Plummeted The journal 'Science' says that
the population has shrunk by
three billion over the past 50 years. Cornell conservation scientist Ken Rosenberg, via NPR The report adds that most of the
drop, around 90 percent, relates
to just a handful of types. These include
finches and sparrows. Other recordings show a one-third fall
in shorebird numbers. The population of grassland types has
also dropped over 50 percent. To get their results, the study's authors observed migration patters
over a period of 10 years. They also used analyzed surveys from
bird watchers in North America. Researchers say there are many reasons
for the drop, including habitat loss
and toxic pesticides. Michigan State University ecologist Elise Zipkin, via NPR