The great night heron mystery at the National Zoo In Animals, Research News, Science & Nature, Video / 20 October 2014 Each year, a mysterious group of night herons flock to Smithsonian’s National Zoo. Then, they vanish. In episode three of our series, we go behind the scenes with the zoo’s caretakers as they investigate why. Related posts: Cats Don’t Roam in Places Coyotes Call Home Poison dart frog toxins best suited for deterring biting arthropods, research reveals In modern amphibian “ark,” new species added with due diligence National Zoo’s red pandas named “Pili” and “Damini” for stormy night Tags: birds, conservation biology, migratory birds, Smithsonian's National Zoo