The experimental removal of the females from 5 breeding pairs of starlings caused the males to change both the quantity and quality of song when compared with 6 unmanipulated control pairs. The increase in the duration and commonness of warbling song after mate removal supports the idea that this type of song functions as mate attraction and stimulation. In contrast, the species-specific whistled songs are more important after pairing, which supports the idea that they are more involved in male-male interactions.