The target article by Byrne & Russon treats imitation as an achievement that originates from observation. In my commentary I propose extending the database to the role of listening. Referring to current studies on song learning in birds, I suggest that at least some features of this accomplishment also may be based on learning by imitation.

I like Cowan's review of STM properties and especially his suggestions on the role of attention. I missed, however, a consideration of studies which provide evidence for STM properties in animals. In my commentary, I argue that such evidence can elucidate the biological basis of storage limitations, validating this view by discussing mechanisms which constrain the acquisition of serial information in songbirds.