Black Flies Affecting Birds

CEDAR RAPIDS, Iowa (KCRG-TV9) -- Experts say there is an excess of black flies in Iowa this year. You may remember two eaglets in Decorah died partially due to black flies in May.

Iowa State University Extension Professor and Entomologist Dr. Donald Lewis said he could not recall the last time black flies were this bad.

“The weather conditions over the past year have been right for their reproduction and survival, and that’s why we’re seeing more than what’s typical for Iowa,” Lewis said.

Area raptors are especially frustrated with the flies. They are biting nestlings and forcing them out of their nests.

“Birds are just one of their food sources. Black flies like other biting pests tend to go for the easy pickings,” Lewis said.

Wildthunder Wildlife & Animal Rehabilitation & Sanctuary has taken in 15 raptors in just a few days. Founder and Director Tracy Belle said she typically sees one bird every other week.

“They’re coming from all directions of the state,” Belle said. “They’re eating them alive, they’re biting them, they’re causing anemia.”

The flies are forcing them out of their nests, putting them in danger, and leaving them vulnerable to predators. Birds have even fallen into the river, or gotten so weak they did not survive.

“It’s going to reduce our raptor numbers dramatically,” Belle said. “We need the raptors; they’re part of the cycle. It’s very sad these babies are helpless. They’re on the ground, predators are preying on them, bugs are just zapping all of their strength.”

Lewis said there is no practical way of getting rid of the flies. The entire state need to spray and mosquito repellents do not keep away biting flies. He said this year the flies’ natural predators were not able to keep up.

Belle if anyone sees a bird lying on the ground, it is important to contact an animal rescue immediately. She said it will take a few weeks to rehabilitate the raptors currently at Wildthunder, then they will be released. In the meantime, she is looking for volunteers and donations to take care of them.

If you would like to help refer to Wildthunder's post.