TORONTO - Ontario is considering regulations to force owners of tall buildings to take steps to protect birds, which die by the millions each year as they fly into skyscrapers.

Birds are confused by lights left on in highrises at night, and during the day they get disoriented by glass windows that reflect the sky or nearby trees and plants.

Environmental commissioner Ellen Schwartzel takes the Liberal government to task in her annual report for saying voluntary measures are the way to get building owners to turn off lights, install non-reflective glass and window coverings.

A 2013 ruling by the Ontario Court of Justice found reflected light that is responsible for bird deaths is a "contaminant" under the Environmental Protection Act.

Schwartzel says that ruling put a responsibility to regulate on the ministry of the environment, but instead it opted for a voluntary approach to get building owners to take steps to protect birds.

Environment Minister Glen Murray says his staff may have been too quick to reject the idea of regulations, and says he agrees with the commissioner's criticisms.