Connoisseur of Birdsong

Okay, so I'll admit I was a little let down initially when I heard the "legendary song of the nightingale" in class. Emmy had shared her recording of the robin, and I thought that was very pretty, so when I heard we were going to listen to the song of the nightingale, the bird that English poets have showered with praise for so many years,... I guess I thought I was going to be blown away. My initial thought was, "Ugh, I think I liked the robin better," but then after awhile (and especially after hearing the second track, with the two male nightingales "serenading" each other) I realized what all those English poets must have been talking about. If I had to sit and listen to the robin's song for, say, three hours straight, I think I would eventually loose my mind and rip all my hair out. The robin's song is rather repetitive, with many of the sounds it makes being very similar to one another. Though initially not as "pretty," -as I put it before- the song of the nightingale is much more varied, with lots of different and interesting sounds and patterns. All in all, I guess on e could say that the nightingale has much more "range" and much more talent, as bird singers go. I can't help but wonder if this has anything to do with its capacity for memory being greater than that of the robin's -or perhaps it's repertoire is just more expansive, so the chances of repeating patterns too often are minimal.
After hearing the songs of the nightingales recorded from different areas (Greece and the Netherlands, for example), I did start to wonder if certain "dialects" or popular sounds could be found among birds of different regions. I know they're migratory birds, and so they could probably pick up different songs from birds in other areas, but I'm sure that there's no big "show and tell convention" to which all nightingales send ambassadors to share and collect new songs. Birdsong is learned, and so it does stand to reason that songs from the same species would vary. Perhaps this would be most clearly seen through species of different areas that do not migrate, or that migrate to different areas. For instance, do the starlings brought to America sing the same songs that the starlings in Europe do? Would a group of migratory birds pick up the songs of another species while they're on their vacation? Are there popular patterns of song in certain parts of the world? And, most importantly, does anyone know of a bird anthropologist to whom I could pose such questions?