Forest Fragmentation Threatens Bird Diversity

Jun 26, 2018

One of my favorite activities is go on bird watching trips and hang out with knowledgeable folks who can identify birds before seeing them – simply by their calls.

I recently took a trip to Little River State Park in Waterbury where we were looking for warblers. Richard Foye, a long-time birder from South Newfane said he has hasn’t seen as many warblers lately and he also believes songbirds aren’t singing as much because there are fewer insects.

Here there’s no shortage of trees, with three out of every four acres composed of picturesque forests. Yet some Vermonters fear there’s too much forest fragmentation. Scientists note that while invasive species, acid rain, and climate change are well documented threats to the health of mature forests, habitat fragmentation is probably the biggest driver.

Fragmentation occurs when large tracts of woods are bought up, parceled out, and cleared. And according to a recent report from the Vermont Center for Ecostudies this may be the leading cause behind the decline of Vermont forest-bird species such as the Canada Warbler and the Winter Wren.

The study found a 14 percent decline in total birds across 31 unmanaged forests around the state, including the Green Mountain Audubon Center, between 1989 and 2013. And of the 34 most abundant species at the sites, 13 showed significant declines. Insect-eating birds like Chimney Swifts, Tree Swallows, and Eastern Phoebes were the hardest hit, experiencing an overall population loss of 45 percent over the 25-year period

Vermont’s state bird, the Hermit Thrush, has been stable over the 25-year span, likely because it’s less sensitive to habitat fragmentation and other pressures. Meanwhile, the number of Yellow-bellied Sapsuckers actually grew over the study period – possibly due to an increase of dead trees for the woodpeckers to forage on.

Whether our yards include just one tree or masses of flora, switching from lawns to native plants can increase birds’ defenses against a wide range of environmental threats. Not only do native plants offset rising greenhouse gases like carbon dioxide, they provide beauty, support pollinators, encourage biodiversity and save us time, water, gasoline and more.

But perhaps best of all, native plants help the birds, and in today’s world, the birds need all the help we can give them.