As in many altricial species, adult moustached warblers alarm call more at the nest as the breeding season progresses. This study used the experimental human approach method as well as two predator types (plastic snake and taxidermic raptor) placed at the nest to test the anti- predator responses of chicks to parental alarm calls. The probability of chicks making anti-predator responses (ducking and jumping) was strongly correlated with the probability of adults giving alarm calls. Furthermore, chicks reacted selectively to different predator types, tending to remain in the nest in response to aerial predators and to jump from the nest in response to ground predators. A conceptual framework is presented identifying the age of chicks when alarm calls are first given for the brood value, vulnerability and chick reaction hypotheses. These were tested by comparing the intercept of the regression line for alarm calls with those predicted by each hypothesis. The results suggest that the anti-predator response of chicks is the proximate cue for adult alarm calls.