Lights out — or lights on? That's the question that is beginning to roil downtown skyscraper owners and operators as a group of volunteers pushes for a Lights Out Cleveland campaign during periods of bird migration in the spring and fall.

A total of 21 buildings, mostly downtown but also including one West Side building and one in Willoughby, have signed onto a website to support Lights Out Cleveland, an effort to douse lights part of the night when birds are migrating. More than half of those buildings, which include 200 Public Square, US Bank Centre and One Cleveland Center, signed on thanks to efforts by David Hollister, a Newmark Knight Frank managing director, to quietly convince building owners to support the move, according to Harvey Webster, the chief wildlife officer and museum ambassador at the Cleveland Museum of Natural History.

Webster's institution, along with other nature preservation and education groups, such as Cleveland Metroparks, have been pursuing the effort since 2017.

The 21 properties are a small part of downtown, which has more than 400 office, apartment and other buildings according to CoStar, the online real estate data provider. The participants also are scattered, a result of Hollister's person-by-person approach using his business contacts.

Hollister said his effort gained traction over the last three months, in large part due to the looming spring bird migration. He said he worked with Webster to state a business case and to open doors for Webster to make the case for a voluntary effort.

"We're not forcing anyone to do anything," Hollister said. "I started out trying to use the energy-savings angle, but that did not win much support. Focusing on what it does to the birds has the impact."

Webster said Lights Out Cleveland asks participating buildings to douse their exterior lights from midnight to dawn from March 15 to June 1 and Aug. 15 to Oct. 31. Lights can be kept on for special events, he added.

The other element is that a group of volunteers has canvassed downtown during the last four migration seasons to pick up dead and injured birds, to prove it happens here.

The volunteers, led by Tim Jasinski, a wildlife rehabilitation specialist at the Lake Erie Nature & Science Center in Bay Village, have gathered 5,000 birds downed by striking windows on downtown buildings. Of those, 1,600 have been rehabilitated and released.

"We know lighted buildings confuse birds," Webster said, because they disrupt the patterns of star movements around the North Star that birds use to navigate.

About 85% of the birds that are recovered alive can be rehabilitated, Jasinski said, with a drop-sized dose of a prescription noninflammatory drug (similar to ibuprofen), food and some rest.

Jasinski said he became aware of the problem in 2016, when Susan Roman, a since-retired security guard downtown, showed up one morning with birds injured in window strikes. In 2016 alone, Jasinski said, Roman and the public dropped off 16 injured woodcocks at the center.

However, dousing the lights is no simple proposition to Doug Price, CEO of Willoughby-based K&D Group. K&D inherited the Tower Lights CLE effort from Forest City Realty Trust when it acquired the Terminal Tower in 2016. Tower Lights CLE consists of a Twitter account of that name and lighting up the landmark.

"We have a staffer dedicated to tweeting on the account with 32,000 followers," Price said. "We support a lot of causes with the colors we choose. I think downtown would be a more barren place without the lights at night."

Price said he also is not certain it's a genuine problem, as he hasn't seen it.

Webster said falcons, gulls and rats feast on dead birds. City crews or building maintenance crews dispose of them, which masks the problem.

However, Hertz Investment Group of Santa Monica, Calif., has signed up for the effort for its properties here: Skylight Office Tower, Fifth Third Center and the two North Point buildings.

Jeff Caimi, Hertz's Cleveland asset manager, said, "It seems like the right thing to do at low cost for the environment. Our tenants are on board with it."