Regional song variants can shift over time, but it is unusual for a song variant in one region to invade and replace the variants in other regions, especially over large geographic scales. However, this appears to be exactly what is happening with the western doublet-ending song variant of the white-throated sparrow (Zonotrichia albicolis). Although initially rare relative to the typical triplet-ending song in continent-wide surveys in the 1960s, doublet-ending songs became the sole song variant west of the Rocky Mountains sometime between 1960 and 2000. I will present data we have been gathering to show that between 2000 to 2017 this western dialect has replaced the normal dialect all across central Canada/US and as of 2017 the transition to the eastern dialect is now east of Toronto, Ontario - a rate of spread of over 150km per year. I will present migration tracking data to suggest that overlapping wintering grounds of eastern and western birds may be facilitating the spread, as well as why this dialect may potentially have taken hold.

The Natural Resources & Environmental Studies Institute (NRESi) at UNBC hosts a weekly lecture series at the Prince George campus. Anyone from the university or wider community with interest in the topic area is welcome to attend. Presentations are also made available to remote participants through Livestream and Blue Jeans. Go to http://www.unbc.ca/nres-institute/colloquium-webcasts to view the presentation remotely.

Past NRESi colloquium presentations and special lectures can be viewed on our video archive, available here.