These were mobbing calls—abrupt, short, loud, and repetitive—alarm calls made in response to predators that are not moving at high speed and so are not an immediate or intense threat—usually a terrestrial predator like a snake or cat or, in this case, a perching bird. The call alerts other birds and signals them to fly toward the source of the call and join in with their own mobbing calls, or attack or mob the predator to drive it away. “There’s a predator here! Come help me harass it!”
