Flexibility in use of signals can provide cues about the function of these signals.

Calls of campo flicker nestlings appear to be directed to conspecifics, as ‘call-for-help’ signals.

‘Scream’ calls could also attract secondary predators.

The type of call used seems to be an honest indicator of nestling condition.

Individuals in poor condition seem to give ‘week’ calls as the ‘best-of-a-bad-job’.