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Habitat characterization of Bicknell's Thrush

I've been busy with a season extension at work, working on a project investigating habitat preference of Bicknell's Thrush. Bicknell's Thrush is SARA (Canada Species At Risk Act) listed as Schedule 1 Threatened and listed as Threatened by COSEWIC (Committee on the Status of Endangered Wildlife in Canada), and has an extremely limited breeding and wintering distribution. For breeding; they prefer dense, high elevation boreal forest, restricted to parts of Quebec, New Brunswick and Nova Scotia, Canada and the tops of some mountains in the New England are of the USA, and winter in dense tropical forest, primarily in Hispaniola.
The national park I work in seems as though it should have plenty of habitat to support Bicknell's thrush, but results of monitoring conducted by Bird Studies Canada (BSC) have been patchy, and some of the survey routes in similar habitat just north of the park have been more reliable. As a result, some coworkers and I have been working on characterizing the forests along the survey routes, measuring things such as stem density, tree species composition, crown closure, stand height and age, branch density, basal area, etc. from several points varying in Bicknell's detection reliability. The hope is to figure out exactly what charateristics determine use/occupancy by Bicknell's thrush, and potentially encourage those conditions within the park in order to better protect this threatened species.

Last week we had a helicopter in so that we could more efficiently access some of the remote sites. The BSC folks camp when they come through in the spring, but, given the weather, that is a less realistic option for this work. the weather last week was unfortunately spotty, with an unstable system in the area, resulting in intermittent winds and fairly intense flurries by the afternoon. We had planned for two half-days and one full day of field work while the helicopter was here, but had to adjust with the conditions. Poor weather on Tuesday morning delayed the helicopter's arrival, so we started later in the day than I would have preferred and only had time to measure three subplots, and gather a lake water sample (for another project). Wednesday and Thursday we started early to take advantage of the morning light, since by 4pm flying would be getting dangerous (in the dark landing away from helipads). While we were out Wednesday, we were watching the skies while we worked, as snow was predicted. All the same, by about 1pm we were suddenly struck with some fairly intense snow, which grounded the helicopter... it was looking like we might end up stuck in the middle of the park for the night. There was an old cabin near one of the lakes that we were prepared to use if we were stuck, but around 3, after we had completed a few more plots, there was a breif window in the snow system (we could almost see some sky!) and we radioed in to the office. The pilot took off and came to get us... but by the time he arrived, the system was closing in again. To his credit, he managed to land in the clearing we found and got us back out!
Thursday we head back out to the area again for the morning. The cabin we were going to use if we had to was between two of our plots, so we stopped to check it out... a window was missing, there were only 3 pieces of wood, and the propane tanks for the stove were empty! If we had been forced to stay the night in the woods, it would have been a damn cold one! We were pretty lucky the pilot braved the weather to get us. We continued on with our work, and, again, the weather started to shift around noon, but it wasn't so fast this time. We were extracted shortly after to return back to the office. With that, the pilot was able to head back out for home, and our back-country work was done. We did 8 of 9 plots... which was pleasing, as I wasn't certian we'd get them all done if we'd had the full time allotted to us. Given that we lost about 3-4 hours of field time due to the weather, and we almost completed the inventory, I'm pretty pleased.

I've been playing around with the data we collected, though there's still a few more subplots to measure (within driving range), and teaching myself to use R. It should be interesting to finish the data collection and analysis to see what comes out of it!

This is a site map of our plots. The green area is the extent of Cape Breton Highlands National Park of Canada.

2 blog comments below

I should send a link to this post to a friend of mine who is a birding enthusiast - he's from British Columbia but lives in Hungary right now. He wrote a poem on "Ode to a thrush" .... some time ago. Must check whether I can dig it up. Great post Ankhanu! Cool
deanhills on Tue Nov 25, 2014 10:32 pm
Hah, an interesting title for a poem, indeed. I wonder if it has something to do with their fluting songs??

Thanks, Dean.
Ankhanu on Wed Nov 26, 2014 6:27 am

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