White-throated Sparrows are familiar to many of us. Seen at some point during the year in most parts of North America, they are well-known for their easily identifiable calls. The sound of “Oh, sweet Canada, Canada, Canada” wafting in the breeze is a sure sign that you are in the presence of a White-throated Sparrow. But birdsong can be a fleeting and changeable thing. White-throated Sparrows for example, seem to forget their mating and territorial calls in the silence of the winter and have to relearn them again in the spring. We also know that they seem to learn how to sing from their fathers. But there is new research which indicates that these birds have recently created at least one divergent dialect.
Sometime between 1960 and 2000, the sparrows in Prince George, British Columbia got creative and started dropping the “da” in Canada, making their new localized song “Oh sweet, Cana, Cana, Cana.” Ok, well that’s fine for birds in that area, and you would expect it all to end right there. But what happened next was very unusual. Almost as if these sparrows had their own social media, this dialectic change went “viral” in evolutionary terms. In other words, it spread nearly 2000 miles to birds in eastern Canada within a very short period of time. How did this happen so quickly? Scientists equipped some sparrows from the west and the east that sang this new doublet and discovered they all overwintered at the same place in Texas and were teaching each other this new apparently more cool version of their well-known song!
But to make matters even more confusing, birds from Prince George are now again modifying their newly modified dialect to something even a little more different! What happens next is anyone’s guess. For more on this research project check out this article from Audubon.