Final answer:
The behavior of birds touching each other to signal the presence of a predator is a communication signal, used to alert others within their group to potential danger.
Step-by-step explanation:
The "Rim Em Eaters" hand sign is not an officially recognized term in the study of animal behavior. However, based on the question, it appears to be related to a behavior observed in birds. Given the options provided and the information referenced, the action of birds physically touching other birds using tactile signals when they observe a predator entering their location is best categorized as a communication signal. This is because the purpose of such a behavior is to convey information about potential threats to other members of the group, helping them react appropriately to avoid danger.