Vanessa, my aforementioned mentor John (who works at the Museum of Natural Sciences), Edward, an NC State student who does a ton of stuff with John like we do, and me were the four researchers during this mountain trip. We slept in the first day (a blissful 6:30am. . .WAIT WHAT my body screamed), and drove up some more mountain before reaching the beautiful Ridge Junction Overlook, whose elevation is 5,160 feet. I could see Mt. Mitchell, the tallest peak east of the Mississippi (6,684 ft tall), Potato Knob (yes, that is the name of it--it's better than Little and Big Butt, which are two other mountains in this region), and Mt. Gibbs. This habitat--that is, habitat in the mountains above 5,000 feet--it's called spruce-fir, because there are, you guessed it, a lot red spruce and Fraser fir trees that make up the terrain. Firs have majorly declined in numbers, though, because of an invasive pest called the balsam woolly adelgid. Anyway, think of elevation as latitude, since the tops of the Black Mountains habitat is equivalent to southern Canada. As elevation rises, the habitat is more similar to the rising of latitude. I think it's pretty amazing, the way habitat is so diverse and confined, yet correlations can be made between regions.
The Black Mountain Range
After looking out at the outlook(ing), the team went to Bald Knob Ridge Trail, the location of all of our soon-to-be thrush subjects. This new study was focused on Hermit Thrushes (Catharus guttatus), who are not very well-researched at all. A couple living in the mountains have found the first few Hermit Thrush nests in North Carolina. This study is seeing how the thrushes move around their territories during breeding season, and how big their territories are in general. If we are lucky, we will find a nest.
Hermit Thrush (transmitter frequency 150.615)
We split up--John and Vanessa pairing up, and me and Edward together--and set up mist nets first. Mist nets, as I've explained in my first post, are volleyball-like nets (with way smaller holes), that have five pockets that birds fly into relatively harmlessly (unfortunately, with research, there are always exceptions, and birds do rarely get injured in these nets). We did playback (playing a recording of a bird song) to incite the hermit thrush males to the site and hopefully fly into the net. John and Vanessa got a male shortly after starting playback, and Edward and I met with them to put the radio transmitter on the bird. Radio transmitters are small devices that send out a signal at a certain frequency. Their battery is a hearing aid battery, and the transmitters have to be light enough to not add too much weight onto the birds (under 5% of a bird's body weight). There is a tiny antenna thing going out of the transmitter so that it can actually emit the signal, and it looks like a black, stiff string. The transmitter goes onto the bird like a backpack, where you have to tie a string (it's actually surgical string so it's a little flexible) into two loops that the bird's legs go into. The transmitter, with the antenna counterpart, goes on the back of the bird, so the bird is of course still completely free to move and fly. If, in a case where the transmitter is on too tight (the loops were tightened too much), this can be seen when the bird is released to go off and be a bird--it won't fly upward, or it won't fly at all. Then biologists run over to the bird to capture it and take the transmitter off. This is rare, though!!
So, when John and Vanessa caught the first Hermit Thrush, we put a radio transmitter on him. All of the birds that we put transmitters on (three total) were males, because the males are the territorial, I'm-gonna-protect-my-mate ones of the relationship. The females are incubating at this time in the summer, or are feeding their chicks with the males. Or, they're forever scoping out other males' territories to see who has the best territory--better territory to them = better male which could = better survival for offspring. Females, essentially, usually stay out of territorial confrontations, because they are doing their own thing, sometimes behind their mates' backs. Keep in mind that I am generalizing. Anyway, that is the long-winded way of saying that, over these two days we caught three males and put transmitters on them, and they got caught in the nets because they were being defensive of their territory. We played a recording of a Hermit Thrush song so that the males would think that a male was singing in their territory. It was teamwork, strategy, and skill all combined and it was amazing. It was amazing to work hard and with purpose, doing the work of a researcher. Camping was fun too, though it takes time to adjust to cooking with a propane stove, and having to put every single item of food in the car so as not to attract bears. That was scary, but no bears were encountered during the making of this study :)
Hermit Thrush Subjects
Radio Telemetry...is hard
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| Vanessa and John putting a transmitter on a bird. V is trying to brush feathers out from under the string of the "backpack" (the transmitter), so that, when the thrush preens later, the feathers removed from under the string do not make the transmitter loose enough to allow the bird to get out of it (this has happened before). |
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| See the black stiff string sticking out? That's the antenna of the transmitter. The transmitter's core is the gadget in the center of this thrush's back. And the backpack part are the two loops coming out from the transmitter's core--one loop for each leg. |
Transmitter Frequency 150.615
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| For all of the birds that we put transmitters on, we did what is called color banding. We always put the regular silver band with the unique number on it, but we also added a few colored, plastic bands to the feet so that we could identify the individual without using technology (like the radio telemetry receiver, or having to somehow read the unique silver band number to see what bird it is). |
Transmitter Frequency 150.659
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| This was the second thrush that we put a transmitter on. These color bands proved to be very helpful a few weeks later as we banded more thrushes and had to be able to identify them by the color combination on bands. |
And there was another bird that we put a transmitter on, but I do not have those photos right now.
