how does the first one communicate to each other?
They make various sounds when communicating.
Turtle
While typically thought of as mute, turtles make various sounds when communicating. 
what is black-shouldered kite? It is a small raptor found in open habitat throughout Australia. how did it get it's name?? UNANSWERABLE do they face any threat? No what do they predate on? grasshoppers, rats, small reptiles, birds and rabbits. can you give a few examples for the third one? turtles, crocodilians, snakes, amphisbaenians, lizards and tuatara.
wiki:19582390
Turtle [SEP] Communication
While typically thought of as mute, turtles make various sounds when communicating. Tortoises may be vocal when courting and mating. Various species of both freshwater and sea turtles emit numerous types of calls, often short and low frequency, from the time they are in the egg to when they are adults. These vocalizations may serve to create group cohesion when migrating. The big-headed turtle is said to growl when removed from the water in an effort to scare off predators. Turtles also have non-vocal ways of communicating that may be employed during courtship. For example male slider turtles use their long foreclaws to stroke the female's face while courting.