Bird lovers across Cyberspace have arrived at the Migration Celebration. When the trillers are a no-show, Professor Bobson knows something is amiss. After he cancels the event, phone calls and social media posts start reporting triller sightings all over Cyberspace. The Professor and kids recruit dozens of citizen scientists to record their observations when they see a triller. When all the citizen scientists have reported back, it leads to a shocking discovery. What is the data telling them? Part of the "Cyberchase" series.