Birders all over North America love their chickadees. In Southern Ontario, we generally have the pleasure of year-round company with the black capped chickadee. This cute little bird might bring a smile to a nature lover in the dead of winter with its cheerful disposition and overall cuteness. While other birds migrate south for the winter this one sticks it out with us, and simply asks for some sunflower seeds, a weedy field or a forest to forage in return.
But a recent research paper and corresponding video have shed light on an interesting onithological fact: The boundary between Carolina Chickadees and Black Capped Chickadess is moving north! Watch the following video, and pay close attention to the four-part call of the Carolina Chickadee. This quad-toned call is the main differentiating factor in the identification of the Carolina Chickadee:
So I checked out the range map on Ebird for the Carolina Chickadee and limited the sightings to this year [link]. Check out the screenshot below of how far north (in Ohio) the bird is showing up, and this data is just for this year, a particularly cold winter.
I'm pretty amazed how close this bird is to the Michigan/Ohio border. I might bundle up a drive to Magee Marsh, Toledo's Oak Openings Metropark with a trip to see this quad-toned chickadee.
I was wondering what the rate of northward advancement was, and according to the researcher Scott Taylor at Villanova University, "the rate of hybrid zone movement of the chickadee hybrid zone recorded in Ohio (1.0–1.6 km/year)" (Taylor et al). So in theory, its not a matter of if this bird makes it to Essex County, but rather, When? But even if you just consider the distance of 60km north (to the north shore of Ohio), it would take about 37 years (60km/1.6km/y) at the current rate of northward movement. It would be even longer if you consider another 60 km to cross the Lake Erie archipelago of islands spanning the border of Ohio and Ontario.
What defines this line between the Southern Carolina Chickadees and the Northern Black capped Chickadees? The report hints that regions with an average temperature of -7 or warmer are tolerated by Carolina Chickadees, so this is what defines that line across Northern Ohio, not a habitat boundary. Taylor states: "The northern range limit of P. carolinensis is not coincident with a physical boundary or habitat shift, but instead closely aligns with the mean minimum winter temperature - 7 C isotherm"(Taylor). So, don't hold your breath for this chickadee to take up residence in Essex for a while. Vagrants can always happen though... So keep your ears peeled for this southern four-toned chickadee!
Taylor Scott et al, Climate-Mediated Movement of an Avian Hybrid Zone, Current Biology 24 , 671–676, March 17, 2014 WEB April 2, 2014, http://www98.homepage.villanova.edu/robert.curry/Documents/RLCpubs/Taylor.2014.pdf
Youtube Video Cornell Research update: New chickadee study shows climate change affecting distribution, LabofOrnithology, 6 Mar 2014, WEB, April 2, 2014, https://www.youtube.com/watch?v=n81Pwweb62Y
PS: Blog readers may remember that a few years back, (during my west-coast vacation) I had achieved the coveted birding accomplishment: The Chickadee Grandslam!