(University of Massachusetts at Amherst) Every spring and fall, billions of birds migrate across the United States, largely unseen under the cover of darkness. Now a team of researchers led by computer scientist Daniel Sheldon at the University of Massachusetts Amherst plan to develop new analytic methods with data collected over the past 20 years — more than 200 million archived radar scans from the national weather radar network — to provide powerful new tools for tracking migration.