Perhaps you've seen a change in bird populations right in your own backyard. Perhaps your bird-feed seems to last a lot longer than it did in the past. Slightly over a hundred years ago, "Martha the passenger pigeon" passed away, and her entire species unfortunately disappeared with her. But few of us took notice of this decline, since there still seemed to be a lot of pigeons, and their abundance obscured their downfall. Today, a similar occurrence is happening with other speces.
History repeating itself across avian world
A new research study analyzed data on birds estimates that North America's bird populations have fallen by 29 percent since 1970.
That’s approximately 3 billion fewer individuals than there used to be, almost fifty years ago. “It’s a staggering result,” says Kenneth Rosenberg from Cornell University and the American Bird Conservancy, who led the analysis.
“This is a critically important study,” says Nicole Michel, an ecologist at the National Audubon Society. Past work has shown that specific groups of birds are declining. However, this is the initial study to put a number on the full extent of these losses.
Sparrows, warblers, blackbirds, oh my . . .
Surprisingly, this research illustrates that the most common birds have been hit the hardest.
“The common wisdom was that we’d see the rare and threatened species disappearing and the common, human-adapted ones taking over,” Rosenberg says. Instead, his team found that 90 percent of the missing birds came from just 12 families, and they were all familiar, such as sparrows, warblers, blackbirds, finches, larks, starlings, and swallows.
"Habitat loss," the culprit . . .
This study revealed how many birds were being lost across every type of habitat including grasslands, coasts and deserts. While it did not directly assess what was behind the depletion, scientists believe among multiple causes, the major factor was habitat loss driven by human activity.
"What we saw was this pervasive net loss," Dr Rosenberg said. "And we were pretty startled to see that the more common birds, the everyday backyard birds and generalist species, are suffering some of the biggest losses."
So, that's why dear reader, you might be experiencing losses on the local level. Comment below, if you've witnessed a similar decrease where you live?
Primary Source: Science Magazine