As planes soar and loop over the river tomorrow for the air show that accompanies Thunder Over Louisville, most eyes will be trained on the spectacle. But for the past few years biologists have been keeping an eye on a nearby eagle nest to see how the birds react to the loud, low-flying planes.Kate Heyden is an avian biologist with the Kentucky Department of Fish and Wildlife. She’s standing on the Indiana side of the Ohio River, training her scope at a nearby island.“You wouldn’t think it would be that easy to hide a nest that’s six feet wide, but..." she says.It’s hard to find the bald eagle nest perched about halfway up a tree, because it’s hidden by dense foliage. But Heyden finds it, and trains her scope on the baby and parent eagle currently in the nest.This is the third year this particular eagle pair has experienced the noise and low-flying planes associated with Thunder Over Louisville. But it’s the first year they’ve had a baby, and Heyden isn’t sure how they’ll react.A raptor—the plane, not the bird—nears for a test run before the big event. It’s loud—so loud, the ground seems to shake.Heyden says the worry is that the noise will upset the birds, and cause them to leave the nest, or stop caring for their young. She watches as the plane loops over the island.“You can tell that they noticed; you can see the adult looking up at the plane as it goes over, but the important thing is it stayed with its young, it didn’t leave the nest, so everything went well,” she says.Heyden will be back Monday morning to check on the birds again in the aftermath of Thunder.