President Donald Trump launched an offensive against windmills on Saturday, blasting the renewable energy technology as a bald eagle killer and causing nearby properties’ values to decrease.

“You know, I know windmills very much. I’ve studied it better than anybody I know,” Trump said at the Turning Point USA conference in West Palm Beach, Florida.

He lamented that windmills are costly and not usually not manufactured in the U.S. and that the production of windmills is bad for the environment.

“It’s very expensive. They’re made in China and Germany mostly… very few made here, almost none. But they’re manufactured tremendous, if you’re into this, tremendous fumes,” Trump told the young conservatives at the conference. “Gases are spewing into the atmosphere. You know we have a world, right? So the world is tiny compared to the universe.”

He added, “You talk about the carbon footprint… fumes are spewing into the air. Right? Spewing. Whether it’s in China, Germany, it’s going into the air. It’s our air, their air, everything.. right?”

Trump then claimed that “if you own a house within vision” of a windmill your house’s value is cut in half.

His claim is widely supported by real estate experts, although some argue that it has little effect on property value. These studies, however, refer to an industrial size wind turbine farm, not a singular windmill as Trump seemingly suggested.

The president then attacked windmills for being loud and killing birds, specifically bald eagles.

“They’re noisy. They kill the birds,” Trump said. “You want to see a bird graveyard? You just go. Take a look. A bird graveyard. Go under a windmill someday. You’ll see more birds than you’ve ever seen ever in your life.”

He continued, “You know, in California, they were killing the bald eagle. If you shoot a bald eagle, they want to put you in jail for 10 years. A windmill will kill many bald eagles. It’s true,” Trump said.

The American Bird Conservancy and the U.S. Fish and Wildlife Service both reported that wind turbines kill hundreds of thousands of birds.

The Obama administration greatly increased the number of bald or golden eagles that can be killed or injured by wind turbines before the turbine companies are penalized.

“After a certain number, they make you turn the windmill off,” Trump said about the turbines that kill too many birds.

He continued, “And yet, if you killed one they put you in jail. That’s OK. But why is it OK for these windmills to destroy the bird population? And that’s what they’re doing.”