A flicker of its distinct black and white feathers and the young bobolink instinctively sets off on spring migration, beginning a journey of more than 10,000 miles from South America to the central U.S. Armed with habitual responses to common dangers such as predators and inclement weather, this grassland bird travels a route meticulously charted by its ancestors. But when new issues such as climate change arise, will the bobolink be able to weather the storm?
Intent on discovering how birds are responding to a quickly changing world, Dr. Jeff Walk, conservation planner for The Nature Conservancy, and Dr. Mike Ward, coordinator of the Critical Trends Assessment Program at the Illinois Natural History Survey and a visiting assistant professor in the Department of Natural Resources and Environmental Sciences at the University of Illinois, trekked across Illinois' grasslands, farmlands, cities and suburbs for three years to plot the location of all species of birds they encountered. At the end of their route, the researchers had collected ample data for comparison to similar studies completed 50 and 100 years ago. Their journey documented stories of hardship and hope.
"Grassland birds represent the real conservation crisis in Illinois," said Walk. "As our grasslands have been converted to urban areas and farms, the availability of summer breeding grounds has quickly diminished, with devastating results." In Illinois, where a fraction of one percent of native grasslands remain, the grassland bird community has declined precipitously — by at least 80 percent in the last 50 years. The good news is that the new data could help restore waning species. "At places like Nachusa Grasslands, we now have the information needed to inform land management decisions for the benefit of these birds," said Walk.
The study found that some species have been able to adapt to changes in land cover and climate. The first study done between 1906 and 1909 showed that red-winged blackbirds were found mostly in marshes, and horned larks were found mostly in pastures. But the new data show that both species now occupy agricultural areas. Cardinals, red-bellied woodpeckers and Carolina wrens, confined to southern Illinois a century ago, have moved north and can now be found statewide.
"When we take steps to improve and restore critical habitat types, we see resurgence in bird populations," said Walk. As forested areas have increased over the past 50 years, for example, so have blue-gray gnatcatchers, eastern wood-pewees, and Kentucky warblers. And once threatened birds like sandhill cranes and great egrets have recovered in restored wetlands, such as the Conservancy's Emiquon Preserve. "In Illinois birds that rely on water — especially those eating fish — are thriving," noted Walk.
The research reveals much more than the status of birds, according to Walk. "Birds are indicators of the health of our environment because of their sensitivity to pollution and climate change."
Protecting habitat in Illinois is just a part of the solution. Scientists are addressing these global issues in places such as the Great Lakes. The Conservancy is protecting habitat for the American golden-plover, a bird that migrates through Illinois to nesting grounds in Argentina. It is projected that birds that nest near the poles will be among the first ones severely affected by climate change because that is where temperature changes will be felt first. As scientists across the globe examine the impacts of land use change and climate change on migrating birds, the data gathered by Walk and Ward will provide valuable insight.
"The challenges faced by birds are largely caused by people: the way we grow food, use water, produce energy, and where we chose to live, work and play," said Walk. "People are also the solution to the problems facing birds."
As history tells us, every generation has its challenges.July 01, 2012