Parent–offspring conflict theory posits that parents and offspring differ in the optimal duration of parental care. Accordingly, the timing of the termination of parental care could be contested between parents and offspring. The outcome of this conflict might be related to the degree of parental sensitivity to offspring demand. By cross-fostering zebrafinch, Taeniopygia guttata, chicks of different ages among breeding pairs, we examined whether parents continue parental behaviour for a fixed time period, or are sensitive to offspring age. Parents provisioned chicks in the nest for longer when they received younger foster chicks and for less time when they received older foster chicks. All chicks fledged and became independent at the same age. Our results show that zebrafinchparents extend the period of parental care in response to protracted demands from their brood.