One of the articles I particularly liked when catching up on three weeks worth of papers (have been in the bush for a while), is the recent letter on bird song dialects (Nature 459:564). In the introduction, the authors cite other work that showed that “geographically separated [bird] groups have local song dialects”. We have a very particular example of this in Belgium, that small country in Europe divided into a Flemish speaking northern region and a French speaking southern region. Near Leuven, the ‘language border’ crosses Meerdaalwoud forest. Interestingly, finches in the Flemish part of the forest sing the proper “suskewiet” song, while Walloon finches in the southern part of the forest have a much shorter, atypical song. Bird groups indeed have local song dialects, and the groups do not have to be separated physically.

Singing Chaffinch (Image source: Herzkasper on Flickr)