1) This article could cover a bit more on the vocal learning in other animals such as dolphins instead of focusing on mainly birds. 2) This article could incorporate more anatomical and/or physiological explanations to vocal learning. 3) This article could touch on more comparisons between different species and their vocal learning style. --Ector.6 (talk) 02:05, 2 October 2014 (UTC)
Comparative studies indicate that whistles vary in structure across populations and species (Steiner 1981; Ding et al. 1995; Rendell et al. 1999), with whistle divergence perhaps facilitating species recognition and speciation (Podos et al. 2002).
