There are actually two types of alarm calls: those addressed to one’s group members and those addressed to the predator. The ones addressed to group members don’t necessarily convey meaningful information about the sender (at least this is not the immediate purpose, although these signals can in some cases have an additional benefit of demonstrating ones high quality to group members, see my other comment).
The alarm calls addressed to the predator are thought to signal the sender’s vigilance: “you’ve been spotted, we know you are here, you can’t catch us”. See mobbing. These calls often result in the predator politely taking a leave.
There are actually two types of alarm calls: those addressed to one’s group members and those addressed to the predator. The ones addressed to group members don’t necessarily convey meaningful information about the sender (at least this is not the immediate purpose, although these signals can in some cases have an additional benefit of demonstrating ones high quality to group members, see my other comment).
The alarm calls addressed to the predator are thought to signal the sender’s vigilance: “you’ve been spotted, we know you are here, you can’t catch us”. See mobbing. These calls often result in the predator politely taking a leave.