Methods, apparatus, systems and articles of manufacture (e.g., physical storage media) to implement power efficient detection of watermarks in media signals are disclosed. Example watermark detection methods disclosed herein include initiating a first search interval in which to attempt to detect watermarks in a media signal. Disclosed example watermark detection methods also initiating a sleep mode upon expiration of the first search interval in response to no valid watermarks being detected during the first search interval. Disclosed example watermark detection methods further include, upon expiration of a first sleep interval after initiation of the sleep mode, initiating a second search interval.