It has been an extremely busy summer, thanks in part to all of you who have been recording and posting white-throated sparrow songs for us! Following the launch of this project last spring, we hit the field to record our own western population in Prince George, BC, and got extremely excited when we thought we heard our first triplet-singing male in over 15 years. Upon sonographic analysis, though, it turned out it was just an odd-sounding doublet! However, the field season wasn’t wasted, as we managed to mount 30 geolocators onto the backs of males in our population, and band 30 other control males. Hopefully in spring 2017 we will get more returns to help us narrow down where our western birds are overwintering. In addition to field work we’ve also been processing white-throated sparrow songs from Xeno-Canto and a variety of other sources, and have been analyzing the preliminary data from geolocators placed on birds in 2014.
Tracking migration: Geolocators
Pilot work in 2014 revealed we had some males from our site here in western Canada heading due south and wintering in central to southern California, which is exciting as all the Xeno-canto recordings of songs from Californian birds have turned out to be doublet-ending. Juveniles wintering there may be exposed to tutors singing doublets, and if some of these breed east of the Rockies, this could help explain the spread of the western song variant.
Most interestingly, though, is that a couple of our pilot-project males appeared to cross the Rockies during southern migration and ended up wintering in the Texas/Oklahoma/Arkansas area. So far, all the songs people have posted for this region are triplet-ending, but our geolocators are showing that there are at least a few in that area who sing doublets. As our geolocator birds appeared to return to us by first flying straight north to the treeline of the Canadian Boreal forests, then heading west, it would suggest a lot of birds wintering in that region probably stay put and breed in the north of Canada’s prairie provinces. By our birds joining them during the winter, a few of those eastern males may be hearing doublet-ending adult tutors. That could explain the biggest findings of this summer (see below)!
Tracking song variation: Xeno-canto and Avichorus
Alexandra Mckenna is a student in our lab who spent a large part of her summer classifying all the songs people have posted to date on Xeno-Canto into either doublet or triplet-ending. To this she added our own recordings from western Canada, but also beta tested a new website set up by Environment and Climate Change Canada (ECCC). This is called Avichorus and is something that Xeno-canto users can give a try, as the official launch will be in Nov/Dec 2016. In an effort to increase spatial coverage of Breeding Bird Survey Routes, a number of sites in rural Canada have been surveyed using an Autonomous Recording Unit (ARU) mounted on the top of a car. This vehicle drives and stops along rural routes, recording the point counts for later analysis. ECCC has been doing this annually as far back as 2010, and has routes from Canada’s Northwest Territories through to the Maritimes. In fact, they have so many that they haven’t been able to analyse them all, so they are putting them online and asking people to help them id the birds in the recordings! Alex was able to tap into these and found singing white-throated sparrows from 2010 through 2015 in a variety of locations to add to our dataset of double vs triplet ending songs. Both the Xeno-canto files and Avichorus files revealed something rather startling – the western doublet-ending song has spread much farther east than we had ever suspected!
While a recording trip Scott Ramsay and I had completed in 2004 through Alberta, Canada suggested that the doublets ended somewhere near the eastern border of that Province, by 2010 in both Xeno-canto and Avichorus recordings, the doublet-ending song had become near ubiquitous right across the Canadian prairies and most of western Ontario! As you will see from the updated map, it is looking like by 2015 the transition zone is almost on the longitude that cuts straight through Toronto, Ontario! West of that line, every recent recording we have is consistently ending up being a doublet-ending song. We are currently trying to go through new recordings we are obtaining from eastern Ontario and Quebec to see if we can narrow down the exact line, but if we take eastern Alberta as the transition zone in 2004, we are talking about a spread of the dialect of over 2200km in eleven years! At 200km per year, this is an unprecedented change in regional song-type by an avian species; it is more like the spread of a plague than a typical dialect! At its current rate, we would expect to see it reaching southern Quebec/Vermont within the next year or so, and be into the Maritimes (which are still all triplet-ending songs) within four to five years!
While we are trying to figure out why this song variant appears to be so popular, you can continue to help us track this dialect shift. Not only are we looking for as many songs as we can from Ontario, New York, Vermont, Maine, Quebec, New Brunswick, Nova Scotia etc as we can get, but we still need to record those birds in the western regions where the dialect as passed through – there we need to ensure we aren’t seeing a back-shift to triplet-ending songs. Also, if you are in either California or the south-eastern US where the birds winter and hear birds practicing their songs before heading north this spring, please pull out your phone and get us a few recordings! If you also want to get involved in other bioacoustics-related citizen-science, ECCC would love people to jump onto Avichorus and go through some of their ARU BBS routes and see if you can help identify some of the singing birds. The site allows you to scroll through sonograms of the recordings while listening to them, and if you hear something you recognize you can tag the song directly on the recording with its species id. It is a lot of fun, and will help ECCC track and conserve breeding grounds of North America’s birds.
We will try and update the map again in Jan 2017 adding the locations of males from Avichorus recordings. Thanks to everyone who is participating, and we encourage you to keep an ear out for those whacky sparrows.