LINCOLN PARK — There are holes in the leaves of the prairie plants surrounding the Lincoln Park Zoo's Nature Boardwalk, and that's a good thing.
It's been about three years since the boardwalk opened, and finally, the 14-acre prairie has grown into its shoes.
The holes in the leaves of the grasses and plants lining the half-mile walk are from caterpillars, which along with the butterflies, birds, turtles and fish, are thriving.
"That's beautiful to us," said Mike Davenport, the zoo's curator of horticulture.
For the first three years, the zoo's staff pulled weeds and plants were small.
They pulled invasive species of plants and hoped the prairie would eventually resemble a typical Midwestern prairie in the 1820s.
The $12 million project is finally at that point, according to Brian Houck, the chief agriculturalist at the zoo.
"You start out with the best practices, then you watch and see what nature does," Houck said.
The prairie grasses and flowers have grown higher than ever, thanks to both a mild and wet winter as well as the natural maturation process of plants, according to Houck.
There is still work to be done, and 25 or 30 volunteers meet at the boardwalk twice a week, where they are tasked with pulling weeds.
With the prairie mostly stable, the zoo's staff is working to diversify the plants with the hopes of bringing in more and more species of insects and animals.
"Now it gets fun," Davenport said.
One of the main draws at the boardwalk are the countless butterflies fluttering from plant to plant across the path.
Houck, Davenport and Mason Fidino, the zoo's coordinator of wildlife management, are seeking to increase both the number of butterflies and the number of species.
New to the boardwalk this year is a butterfly garden, which consists of dozens of plants and flowers that will hopefully attract various species.
"Three years ago there were very few species of butterfly," Fidino said. "Now there are 17 that the zoo has identified."
Each year, Fidino with the help of the zoo's interns, has been able to identify two or three new species, but he admits there are others that can't be identified because they are so small.
The zoo's approach to attract the butterflies had a familiar ring: If you plant it, they will come.
"Sometimes it's a matter of a few years, but they will come," Davenport said.
Davenport, who previously created a butterfly garden at the Fairfield Tropic Botanic Garden in Miami, was tasked with making the prairie an attractive stop for butterflies.
Last fall he scoured books, websites and visited obscure nurseries to find strains of plants that could entice rare butterflies.
"We are casting our net wide," Davenport said.
While some of the plantings are admittedly a longshot in their potential to attract rare butterflies, he said it's worth the effort.
"In some cases it's little weeds that are only four inches tall," Davenport said. "You just hope."
Other species are thriving as well.
When the zoo was constructing the boardwalk, it built planks underneath the bridge that crosses the pond. Those planks are now filled with Cliff Swallow nests and baby birds chirping for food.
"We are taking people way further out of the city, but still in the middle of the city," Fidino said.