According to the National Audobon Society, some species of
songbirds have experienced a 30 percent decline in their population
over
the past decade. Now, there’s evidence that non-native plant species
may
be contributing to the problem. The Great Lakes Radio Consortium’s
Karen Kelly reports:
Transcript
According to the National Audubon Society, some species of songbirds have experienced
a thirty percent decline in their population over the past decade. Now, there’s
evidence that non-native plant species might be contributing to the problem. The Great
Lakes Radio Consortium’s Karen Kelly reports:
American robins and wood thrushes like to build their nests in shrubs. Typically, they
choose tall bushes with long thorns that keep predators away. But as those plants are
replaced by non-native species, the birds are forced to move into the new shrubs. And
that makes them vulnerable to predators.
Christopher Whalen is an avian ecologist with the Illinois Natural History Survey. His
study found birds that nest in exotic shrubs were twenty percent more likely to lose
their eggs to a predator.
Because of the different way these plants grow, the exotic shrubs provide a
suitable-looking confluence of branches at a lower height above the ground. So, nest
height drops a meter and a half to two meters on average.”
That makes it easier for raccoons to invade. Whalen’s study focused on Illinois, but
he says birds are doing this throughout the Northeast and Midwest.
For the Great Lakes Radio Consortium, I’m Karen Kelly.