URBANA — Those blinking lanterns in Crystal Lake aren't runway lights to help geese land in the water.
Far from it.
The flashing lights are designed to keep the ever-growing goose population out of the lake.
Urbana Park District officials placed 14 solar-powered blinking lights in the lake late last month in hopes of deterring Canada geese from using the lake and harming its water quality and the surrounding park land.
Last fall, said park district project manager Derek Liebert, as many as 90 Canada geese were making the north Urbana park their home. Even greater numbers had been observed in spring and summer months, he said.
"The geese graze heavily on turf and shoreline areas and contribute to erosion and to poor vegetation establishment," Liebert said. "Significant accumulation of geese droppings detracts from popular activities such as picnicking, fishing, boating and walking on trails. And fecal contamination has begun to observably affect Crystal Lake's water quality."
Last summer the lake began to show the effects of the increase in the number of geese.
"It potentially could affect the fish population over time. Right now we're most concerned about the high nutrient levels in the water," Liebert said. "We sort of had a record year in terms of duckweed this last year. That was a real indicator for us because we had never had the sort of challenges with duckweed before."
Furthermore, there have been increased complaints from park users, he said.
It's unclear for now whether the flashing lights are bothering the geese.
"We actually put them in just as the lake was freezing so the geese were already moving out. The real test will be this spring when they come back and the water is open," Liebert said. "Historically, we have a few geese, even in the winter, if there are some open spots. But they had all flushed off by the time we started putting the lights in place."
The lights, which cost the park district about $4,000, don't harm the birds, according to Liebert.
"It disturbs their sleeping pattern. The folks who developed this approach tell me that it sort of mimics the flash of a predator's eyes and causes them enough distress that they move out. They tell us that geese sleep in the water so that having these in the water is a deterrent of sorts," he said. "I found one place where they didn't work, but the vast majority of folks who have them were pleased with them."
"It's something we've been looking at for a long time. This is the closest thing we found to a silver bullet. They've been using it at the arboretum (on the south side of the University of Illinois campus) and in a couple places in southwest Champaign with some success. So after visiting with them and doing some background reference checks, we thought it was worth trying."
At the UI, said arboretum director Bill Kruidenier, four lights, installed last spring, have "worked well for us. They've been very successful."
The goose problem developed on the approximately 1-acre pond at the arboretum when invasive plants were cleared from around the water.
"We began replanting with native plants. But before they had a chance to grow up, we have probably 100-plus geese fly in. That's when we began to investigate what we could do to discourage their living there," said Kruidenier.
"We came up with this flashing light thing and all but one couple left, and they had already laid eggs. They did not leave until after the goslings could fly. Once they could fly, the two adults and four goslings took off and they haven't returned."
To be doubly sure, Kruidenier said, UI crews put chicken wire fencing around the ponds.
"They like a clear walking path between the water and the ground so we put up the fencing to discourage them," he said. "That was more of a hedging the bets because of the investment we made in native plants. We just wanted to be extra careful."