ha. That's the like question my dissertation didn't answer.
The short answer is that they do everything. It would really depend on what the context what. Birds usually have 2 or 3 different kinds of alarm and alert calls for when a predator is around (often different for hawks vs. terrestrial predators like cats). They may have a number of different social calls, for contact, indicating food, begging for food, what have you. There are calls used in aggressive encounters, to prevent or stop fighting. Some birds have copulation calls, or calls given before or after copulation to coordinate male and female behavior...
Since you say "going OFF", my best guess is that some predator had gotten a chick, and the parents were going as berserk as they could in an attempt to save it. But that's pretty much a best guess. It could have been two birds having an aggressive encounter, too. And mynas mimic, I think, so you could hear a whole lot of variety out of them.
Seriously, I tried studying why some species have large call repertoires and some have small ones. Deep stuff. Very confusing. Still confuses me.
The short answer is that they do everything. It would really depend on what the context what. Birds usually have 2 or 3 different kinds of alarm and alert calls for when a predator is around (often different for hawks vs. terrestrial predators like cats). They may have a number of different social calls, for contact, indicating food, begging for food, what have you. There are calls used in aggressive encounters, to prevent or stop fighting. Some birds have copulation calls, or calls given before or after copulation to coordinate male and female behavior...
Since you say "going OFF", my best guess is that some predator had gotten a chick, and the parents were going as berserk as they could in an attempt to save it. But that's pretty much a best guess. It could have been two birds having an aggressive encounter, too. And mynas mimic, I think, so you could hear a whole lot of variety out of them.
Seriously, I tried studying why some species have large call repertoires and some have small ones. Deep stuff. Very confusing. Still confuses me.
Finally: not a dumb question.