Bird Migration Day

World Migratory Bird DayMay 11-122013

A flock of birds fly over a park in Yuncheng City, north China's Shanxi Province, on Oct. 26, 2011.

A flock of migrating starlings flying over a field near Netivot in Israel, on Jan. 25, 2013

A flock of birds in Ahmedabad, India, February 6, 2012.

A flock of starlings fly over an agricultural field near Netivot in Israel, on Jan. 24, 2013.

A flock of starlings fly over an agricultural field near Netivot in Israel, on Jan. 24, 2013.

A flock of birds gather in Liernais, France, on December 23, 2012.

A flock of migrating starlings flies near Netivot in Israeli, on Jan. 25, 2013.

A flock of birds gather in Liernais, France, on Dec. 23, 2012.