A group of falcons is commonly referred to as a “cast.”
This term originates from the old practice of falconry, where hunting birds like falcons were often trained and flown in groups by falconers. The word captures the essence of these birds working together, showcasing their incredible speed and hunting skills. While you might hear other terms like “a flight of falcons,” “a plume of falcons,” or simply “falcons,” “cast” is the most widely accepted term in ornithological contexts.