If you visit South Russell Park on a given day between May and August, you may hear a cacophony of looping whirs and beeps coming from the tall grass. Take a look. You might not spot it at first, but look closely and you’ll see that the almost unnatural sound is coming from a small songbird, the back of its head a bright yellow crown visible between the stalks.
And yes, Ohio Department of Natural Resources Joseph Lautenbach said, the call sounds a lot like iconic Star Wars robot R2-D2.
The bird is called a bobolink, and that tiny singer flew more than 5,500 miles to nest in South Russell’s trademark tall grass for the summer.
“They have a unique song,” Mr. Lautenbach said. “It’s kind of like a bubbly song, it kind of jumps around a lot.”
The bobolink’s mating call is just one of the bird’s attributes. Everything about its behavior patterns, from migration to habitat, goes against many of the traditional notions of bird behavior.
South Russell Councilwoman Cindy Nairn, who heads the village Parks and Properties Committee, said residents are respectful while the small birds are nesting over the summer with park groundskeepers working around the bobolinks.
“Our park was the Muggleton Farm,” she explained. “Our village bought the farm, and in conjunction with Western Reserve Land Conservancy, the park was officially open in the early 2000s.”
Mrs. Nairn said that the Muggleton Family grew hay and other vertical, grassy crops and would cut their hayfields multiple times a summer. When the village was in the process of acquiring the land to convert it into the park back in 2006, nobody cut the field for several months.
“While we were negotiating with the Muggleton Family to purchase the property, all of a sudden this huge amount of bobolinks just showed up on this property,” she said. “It is the largest bobolink population in Geauga County, and it just happened on a fluke because of what the Muggletons planted there and what was allowed to grow.”
Unfortunately, Mrs. Nairn added, South Russell had to learn to wait to cut their grasses the hard way, after a groundskeeper was hired to trim the grass before September, when the bobolinks take flight to southern regions. “It was a disaster,” she said of the early mowing.
Since then, the village has added a new section to the park’s acquisition management plan, which states that the South Russell Service Department will only mow the field after Sept. 1 or before April 1 of a given year, to ensure that the nests remain unharmed.
What’s so special about bobolinks during their annual summer nesting in South Russell?
“People like bobolinks because they are a beautiful bird,” Geauga Park District Field Biologist Tami Gingrich said. “Easy to listen to when nesting and great fun to listen to so a lot of people just really, really love to see them.”
“The males, as everything written about them will say, look like they have a tuxedo on backwards,” explained Andy Jones, curator of ornithology at the Cleveland Museum of Natural History. “It’s a really distinctive looking bird with an impressive breeding aerial display that the males do. I’m really into migration and so that’s one of the reasons I like the bobolink so much. It’s one of the longest migrations of a songbird in the western hemisphere.”
When he thinks of songbird migration, Mr. Jones said he tends to thinks of species like warblers, orioles and thrushes, which prefer spending their winters in Central America or the northern part of South America.
The reason for the long journey is the same reason that they fancy nesting in places like South Russell Park, which Mr. Lautenbach said is home to a wide variety of forbs, leafy plants, that serve as perfect cover for bobolinks to build their ground-level nests.
According to Rodrigo Lorenzón, a researcher with the National Council for Scientific and Technical Research in Argentina, bobolinks stop for brief respites at a wide variety of grasslands depending on what stage they’re in along their continental journey, from steep prairies that never flood to soaked river floodplains.
“In both breeding and wintering grounds,” he explained, “bobolinks use different types of grasslands. Cultivated grasslands have replaced natural grasslands originally used by bobolinks becoming the majority of its current habitat.”
Now, he said, the birds use “upland prairies comprised of a mixture of grasses such as those of red clover, dandelion, monocultures of switchgrass and grasslands along river bottomland habitats.”
Occasionally, they fly through. Mr. Jones said that a study published by the American Ornithological Society in 2018 found that the birds will sometimes fly over solid ocean for four or five straight days.
“A few of them actually left New England,” he said, “flew over the Atlantic Ocean and didn’t land until they hit South America. That’s really extraordinary for such a small bird.”
When the birds are migrating or living out the winter months, Dr. Lorenzón said bobolinks, which poet William Cullen Bryant dubbed “Sir Robert of Lincoln” in his poem of the same name, prefer the amenities of freshwater grass and shrublands that crop up near rivers.
Those same types of environments are more likely to be present in the Pampas region, a collection of fertile plains that encompasses all of Uruguay in addition to portions of Argentina and Brazil. Most of northern South America, on the other hand, is forested land.
“As the size of the grasslands decrease, they’ll be less likely to use it,” Mr. Lautenbach explained. “We call that area sensitive. There has been work done in Maine that says the probability of a grassland being used by a bobolink was only 20 percent when the field was 100 acres in size. The bigger the grassland is, the more likely a bobolink is going to use it.”
The preference to nest, eat and live in fields presents the bobolink with its greatest challenge, habitat loss
“They are not technically listed anywhere, but they are a species of conservation concern,” Mr. Lautenbach said. “They’ve been undergoing large range-wide population declines since at least the 1960s.”
Some of the issues threatening the Bobolink population are related to its diet, which Mrs. Gingrich said consists of insects for the nestlings and seeds and grass for the adult birds as they migrate.
“They face a lot of perils during migration because people shoot them because they do damage to the rice fields,” Mrs. Gingrich explained. “People shoot them, they’re trapped and sold as pets in Argentina, people in Jamaica eat them.”
Other problems pop up when it comes time for the Dolichonyxoryzivorus (the species name literally translates to “rice bird” in Latin) to leave North America in August. In the 1800s, Mr. Lautenbach said, the birds would travel along east coast marshes and river corridors where wild rice was plentiful.
Once that land started being developed in the mid-19th century, Bobs of Lincoln were cut off from a key food source that helped sustain them on the first or last leg of their journey.
“We’ve changed land use over the past couple hundred years, and they’ve probably moved eastward into New England as we’ve created more pastureland there,” Mr. Jones predicted. “A lot of the grasslands birds are shorter distance migrants and they might go into Texas for the winter, but that’s not the behavior that bobolinks picked up.”
The same is true in the southern hemisphere, where Dr. Lorenzón said they feast on crops of soybeans, different types of corn, sunflowers and sorghum.
Why bobolinks travel to the northern United States instead of the southern regions is unknown, Mr. Jones said, because researchers have not observed the evolution of this pattern.
Selecting Earth’s floor
Why these birds nest on the ground also remains a mystery to experts.
“They’re taking their chances on the ground, but birds that nest in trees are just as vulnerable to squirrels and things like that,” Mrs. Gingrich said. “It’s really just how they’ve evolved. They are a grassland bird, that’s how they’ve evolved and that’s why they nest on the ground.”
Mr. Lautenbach agreed that some birds have just grown to prefer to nest on the Earth’s floor, where they are safe from birds of prey like raptors but are at greater risk of being feasted on by raccoons, foxes and coyotes.
Humans are another threat to the ground-nesting birds. Mrs. Gingrich said many of the bobolinks tend to do their breeding in hayfields, which are being cleared more frequently now than in the past.
“We now hay three weeks earlier than we used to in the 1940s and 1950s,” she explained. “I think probably because farmers want to get as many cuttings in as they can, so if they start early they’ll get a first, second and third later in the summer.”
To ensure that bobolinks have enough time and space, the South Russell Village Park management plan stipulates that employees only mow half of the old field areas once per year so that grass has sufficient time to reestablish itself as a habitat. Groundskeepers are also instructed to set the cutting blade at a height of 6 inches on their mowers.
Mrs. Nairn has received complaints from residents about other parkgoers who were letting their dogs off the leash, endangering the bobolinks nesting in the brush.
Dr. Lorenzón said that bobolinks’ behavior changes significantly as they change continents to breed and winter. If they are breeding, the birds are more aggressive and solitary, he said, but if they are traveling or living in South America they adopt more of a pack mentality.
“Aspects such as the notorious territoriality of males during the reproductive period in North America are not observed during their stay in South America, when bobolinks show a gregarious behavior forming large flocks,” he wrote.
That’s why, Mrs. Gingrich said, people get to bear witness to the bobolink’s call in South Russell Village Park, where males often arrive four to eight days prior to the females.
“So what they will do is they stake out a territory and they see how many females they can get to come and nest in [their] territory and [they] will father all the babies out of those females,” she added. “And that’s called polygamy.”
Mrs. Gingrich said it is common to see the first few baby bobolinks hatch in June, as mothers lay between three and seven eggs and then incubate them for about a week and a half.
“After the eggs hatch, the young are pretty much ready to leave the nest by eight to ten days,” Mrs. Gingrich said. “So they develop real fast. That doesn’t mean they fly away, it means they leave the nest and learn how to feed themselves on the vegetation, but they do leave the nest quite early.”
Mr. Lautenbach said the bobolinks feed the nestlings insects and other protein-rich invertebrates like spiders and snails to help them grow quickly.
It may already be mid-summer and the bobolinks have come to nest, but it is not too late to see their departure, in which Mr. Jones said hundreds of the birds can flock together as they begin their 6,000 mile journey in August from Ohio to South America.
“One of my favorite birding experiences is related to bobolinks,” Mr. Jones said. “I was staying at the beach on the southern coast of North Carolina in September, two years ago, and I went outside at night and could hear bobolink flight calls overhead.
“This was right after sunset, and because of where I was on the coast, if you went south you would just be over open water,” he said. “It’s pretty awe-inspiring. I couldn’t see the birds at all, it was pitch-black, but to hear these birds overhead right at the start of this epic migration was really a memorable thing.”