PLAINFIELD — In the middle of August, you can spy the last of the bobolinks making their way south to their wintering grounds in South America. Bobolinks are in trouble: Recent research reveals that while the farmers whose fields they rely on for habitats are quickly adapting to climate change, migratory grassland birds like the bobolinks are not.
Noah Perlut, an ecologist at the University of New England who led the research, said that the date of the first cut of hay in Vermont has moved about 10 days earlier over the last 18 years. The shift has created a conflict between farmers who need to get the nutritious first cut as early as they can, and the birds whose nests are vulnerable to farm equipment.
“These birds nest directly on the ground in hayfields and pastures. And their nests are incredibly vulnerable to equipment and grazing. When a field is mowed, there’s a 100% chance that those nests are going to fail,” Perlut said.
His research follows Savannah sparrows and bobolinks, both grassland species, closely.
Ten days may not seem like much, but Maeve McGowan, a recent graduate who contributed to the research at UNE, which is based in southern Maine, said that “it can make a huge difference.”
“There are 65 days between parents making nests and babies beginning to fly, and out of 65 days, 10 days makes a huge difference. A few days means that the babies can fly away and escape farm equipment,” she said.
Delaying the first cut of hay also has steep consequences for farmers. Pat McNamara, of McNamara Dairy in Plainfield, said that the first cut on his family’s approximately 450 acres of hay fields is “about a week” earlier than it was in decades past.
He said that waiting to cut the hay impacts its quality “tremendously.”
“The earlier you get it cut, the better,” he said. “The protein is much higher, the energy levels are higher. It makes the cows grow better and milk better.”
Perlut said that dairy farmers, whose fields make up about 25% of grassland habitat in Vermont, have always had to mow early in the season. However, more and more farmers who used to mow in late June and July are cutting their hay earlier.
“Put together, grasslands species are struggling with the timing of mowing on 60% of available habitat,” he said. “Without thoughtful management plans, it’s just not going to work for the birds.”
Perlut said that agricultural uses and optimal habitats do not have to conflict. His recent research is part of a lengthy research project about how hayfield and pasture management impacts grassland songbirds. When the Bobolink Odyssey project began in 2002, he said that the dogma for supporting birds was that farmers had to mow later.
“Inherently, that’s correct,” he said. “But for dairy farmers, there’s not even a conversation to be had because dairy farmers cannot delay their first harvest.”
He said that “the heart and soul of our work” is finding “an alternative model that works for dairy farmers.” If farmers cut as early as mid-May, they can take advantage of young, high-protein hay. If they then wait a full 65 days to make their next cut, the grassland birds will have time to nest and raise their young before the heavy equipment comes through.
The U.S. Department of Agriculture’s Natural Resource Conservation Service offers landowners expert advice on how to manage their fields for grassland birds. The NRCS program also offers financial incentives to landowners to either delay their first cut entirely, or follow Perlut and his colleagues’ model.
Although their needs conflict at times, birds need farmers: Bobolinks depend on fields that are mowed at least annually for their habitat.
Meanwhile, the Bobolink Project, a partnership between Audubon Vermont, Mass Audubon and New Hampshire Audubon, incentivizes farmers to either cut early and wait at least 70 days, or delay all cutting until August.
The group implemented a “CSA model” that gave concerned observers the opportunity to contribute to a fund that would compensate landowners.
Interested landowners in turn participate in a reverse auction, with per-acre compensation of about $50 awarded to the lowest bidders. In 2021, the program secured that landowners would not mow about 1,000 acres across 24 farms during the bobolinks’ nesting period.
Pat McNamara said that although he had heard of an incentive option to change haying procedures, he and his family had never considered it because they cannot compromise the quality of the hay. He said that over the course of a season, an acre can yield about $180 worth of hay.
“We generally have few people enrolled in the program who are making their living off of agriculture,” said Allan Strong, an ornithologist at the University of Vermont who works on the Bobolink Project and also contributes to the Bobolink Odyssey’s research. “For those not involved in farming, it’s just really helpful in terms of paying property taxes … For the farmers, it’s really dependent upon their carrying capacity on their property. For those farmers that have just enough land to support their beef cows or dairy cows, we can’t pay them enough money.”
When Perlut first investigated grassland birds’ response to climate change, he predicted that the Savannah sparrow, a short-distance migrator, would adapt more quickly to the changing climate than bobolinks because their wintering grounds in the American South correspond with northern weather patterns.
Instead, they found that both Savannah sparrows and bobolinks, whose migration exceeds 12,000 miles, failed to adapt.
His yet-to-be-tested theory is that both species evolved for the grasslands of the Midwest where habitat disruptions — such as massive bison herds and small fires — came sporadically rather than annually. Unused to disasters that came every year, they returned to where they nested before.
“They assumed if it came this year, then it’s not going to come next year,” he said.
Claire Potter is a Report for America corps member. She can be reached at cpotter@vnews.com or 603-727- 3242.