Companies that operate wind farms in North Dakota say they're working on tweaks to make sure tractors and migrating birds donât inadvertently set off the lights atop wind turbines at night. Under state law, newer wind farms had to install technology by the start of 2020 to mitigate the lights so that they don't cause an eyesore by blinking bright red all night. The operators have put in radar-based systems meant to keep the lights off unless an aircraft flies in the vicinity. But members of the Public Service Commission, which pushed for the law, say theyâve noticed the lights seem to stay on more often than they had expected.