Professor of Biology Herb Wilson writes that most important in bird species conservation is understanding the types and magnitude of human-related mortality. He points out the two most potent sources of bird deaths related to humans: building collisions and house cats. Wilson argues that the magnitude of these hazards should be the primary motivation for their reduction. Keeping cats as indoor pets, he writes, is the way to go for the safety of both birds and cats, and likewise, improved placement of bird feeders and visibility of window glass can reduce collision-related bird deaths. Addressing mortalities from wind turbines, Wilson also advocates for energy avoidance, reducing the need for power plants in the first place.