True birders are some of the most determined and persistent hobbyists out there. If you want to call bird watching a hobby. For many, it's more like a passion. Many look forward to "Big Day" competitions, where individuals and teams strive to see how many different bird species they can spot in a 24-hour period.

Many birders log their sightings and identifications in eBird, a smartphone application created by the Cornell Lab of Ornithology and the National Audubon Society. The good news is that millions of birders use this app. The concerning news is that their bird sightings over a recent 14-year-period point to population declines in 75 percent of North American bird species.

To learn more about this news, we've invited Dr. Amanda Rodewald from the Cornell Lab of Ornithology and Cornell University to join us today.