Ken Rosenberg, a conservation scientist with the Cornell Lab of Ornithology, is the lead author on a study published in Science that says North America’s bird population has declined by three billion birds since the 1970s. We talk to him about the findings as it relates to Texas, the causes and what we can do about it. Report by Marshall Hinsley. Learn more about environmental issues and sustainable trends in Texas on GreenSourceDFW.org. Full transcript here.