Friday, May 4
DUMMERSTON -- Not all environmental news is doom and gloom these days.

According to local ecologist Hector Galbraith, "Bird diversity in Dummerston right now is as high or higher than it has been in a long time."

For the past five years, Galbraith has been cataloging the number of bird species that breed in Dummerston and several other southern Vermont communities.

His work is part of a statewide project conducted by the Vermont Institute of Natural Sciences, which is compiling its second bird breeding atlas.

On Thursday night, Galbraith presented his findings to a group of 30 bird lovers at the West Dummerston Community Center. The event was sponsored by the Dummerston Conservation Commission.

A similar atlas survey was conducted by VINS in the 1970s, and at that time 91 bird species were identified in Dummerston. Galbraith, so far, has identified 92 species in town.

Galbraith credits Dummerston's land stewardship and diversity of habitats -- from mixed hardwood forest to coniferous forest to grassland and agricultural land -- for preserving the variety of birds.

Roughly 75 of the species Galbraith identified live in forests, while only 10 live in grasslands. The remainder prefer wetlands and more densely built areas.

In the 19th century, about 80 percent of Dummerston's land was used for agriculture. Galbraith believes that probably only 50 species were native to the area then as a result of the deforestation. Since then, local bird diversity has mostly been on the rise, though he estimates it peaked around 20 years ago.

"We're still pretty good, but we've probably lost some of the diversity we've had," he said. "There's no fixed constants in nature. Everything is always changing."

Galbraith pointed to four threats facing the area's bird diversity: estate breakup, increased urbanization, loss of grasslands and climate change.

Northern goshawks, pileated woodpeckers and red-shouldered hawks all need extensive tracts of forest, so as properties are subdivided and broken up, those birds can no longer survive.

Likewise, as the town becomes more and more built up, invasive birds like sparrows and starlings will benefit, but most others will be harmed. A decline in area agriculture could mean fields in which bobolinks tend to nest might disappear. Equally threatening to those birds is poor grassland management -- namely the overhaying of fields.

Galbraith believes climate change has already changed the makeup of the town's bird populations. Southern species like the tufted titmouse, the red-bellied woodpecker and the turkey vulture have all made inroads in Vermont in recent decades.

On the other hand, the northern cardinal and the northern water thrush have been pushed up into northern Vermont and Canada for the same reason.

Galbraith emphasized that most effects of climate change are yet to be seen. Experts simply do not know how shifting climate patterns will alter bird migration and nesting habits.

"For every 100 questions we ask about nature, we have the answers to about three," he said.