The Story of Pronghorn 166

Last year about this time I witnessed the capture of a Pronghorn doe. She was spending the winter just west of Glasgow with a large group of other Pronghorn. She was singled out and captured by a crew using a helicopter and a net gun and then fitted with a GPS collar as part of a research project by Andrew Jakes. The number written on her ear tag is 166. I have previously posted about her capture and location over the summer.



A few weeks ago I received a phone call from Andrew. He had just completed a flight to see if the animals wearing collars for his study were still alive after this extraordinarily snowy winter that has been so hard on these animals. Surprisingly, most of his animals were still alive, but he informed me that 166's collar was emitting a mortality signal (if the collar does not move a certain period of time, the signal changes so that researchers know the animal is most likely dead).



The news wasn't entirely unexpected with the number of animals dying this winter. However, what he told me next was rather remarkable.
Andrew told me they thought she was next to the highway and that she had probably been struck by a vehicle.





That wasn't the remarkable part; lots of Pronghorn have been struck and killed by vehicles this year.
The remarkable part was where it happened.
The mortality signal from her collar told us she was about 9 miles west of Jordan, Montana near highway 200. This location is approximately 70 miles south of where she was captured last winter and in between was Fort Peck Lake and miles of rugged Missouri River Breaks habitat not generally known as winter habitat for Pronghorn.
I had just driven that highway a day earlier and went right past her. My path and hers had crossed again, although at the time I didn't know it. I had noted a number of dead antelope on that trip and I even thought I might know exactly where she was at.



Ten days ago Kelvin Johnson, FWP biologist from Glasgow, and I headed south to find her. We found plenty of Pronghorn on our drive south, all gathered together trying to make it through the winter.

The animal I remembered in the ditch was a buck and about four miles for the spot we were given. About a half mile from the location, we found the remains of about four road killed Pronghorn and figured she must be in this group. The receiver picked up no signals and none of the heads we could find had an eartag. We continued down the road to our given location and found a lot of Pronghorn wintering just south of the highway. But we didn't find 166. No signal. Nothing.



This is the area we were searching in.



We walked around a bit and went to the top of the ridge near the location, and turned the antenna in all directions, but still no signal. We headed home disappointed to not have found her and speculated a number of different ways to explain why we couldn't find her. My sentimental favorite was that she had just stayed curled up for so long that the mortality signal had kicked on but she was still alive and now was wandering around further south. There were two other live Pronghorn with collars in the area (both had made a similar trip as 166), but we didn't pick up the signal from those animals either. Maybe the receiver wasn't working well. Maybe.....

Another flight early last week put to rest my idea that she was still alive. The location of the mortality signal was a bit elusive, but it was still there. A new location, not that far from the old location, was passed my way.

Last Friday I was once again heading down this highway on my way home. I really wanted to be the one to find 166. She had become a special animal to me so I borrowed an antenna from the FWP biologist in Billings and a receiver from another FWP biologist in Roundup and headed north. I had gotten out of town much later than I had wanted and it was starting to get dark when I got near the new location. I knew that the signal on the collar quit for portions of the day but I didn't know when that was. I told myself that if I put the antenna on the receiver and wasn't able to pick up a signal, I would have to try again another day. It was quite cold and blowing when I stepped out of the car and turned on the receiver. I tuned in the frequency, plugged in the antenna and immediately heard loud beeps coming from here collar. I was very close.



The signal directly led me down the ditch on the north side of the highway about a quarter mile when I noticed a leg sticking out of a snow bank and then the top of a Pronghorn head. I pulled the antenna off the receiver and waved the receiver over the head. No signal. Must not be her but I know she is close. As soon as I put the antenna back on the receiver it became very apparent that the antelope I was looking at had to be her. I brushed the snow back from around her neck and there was the collar. I had found her. It was close too - I later found out the transmitter was scheduled to turn off at 5:00 pm and the time on my photos was 4:46.



Above you can see the back of her head with the yellow ear tag. There was a small chunk of wire stuck in the eartag - a testament to the trials these animals undergo each year during their migrations. The prior week she must have been too well buried in the snow for us to pick up a signal from her collar.



Above is a GoogleEarth map where I plotted the known locations we have of 166 from the VHF transmitter on her collar - where she was captured (in the middle), her summer location (top, just north of Limerick, SK), and her final location (bottom) - a line nearly 170 miles long. It was amazing how near her capture location was to a straight line between her summer spot and the point of her demise. But the more interesting part is going to be when we get the GPS locations from her collar to see what she did in between those points and the path she took to get that far south after the snow started. So - more to come regarding the story of Pronghorn 166 and her extraordinary journey.

Pronghorn 166

The Pronghorn (Antilocapra americana) is the sole surviving member of a family that, during the Pleistocene, consisted of twelve species. They are the fastest land mammal in North America and are built for the open plains of the west.



Although speedy, they are poor jumpers and would rather find a way under a fence than try to jump over it. However, they can move surprisingly fast underneath barb wire fences and even faster if the bottom wire is raised even a couple inches above what is traditionally used when constructing fences. Woven wire fences (see the photo above), used to confine sheep, are effective barriers to pronghorn movement.



Roads and traffic are also deadly for antelope during their migrations or when the roads bisect their wintering areas.



The area just north of the Milk River in Eastern Montana is a primary wintering area for a number of pronghorn. We have known that many of these animals spend their summer in Canada from past studies of collared animals, but little was known of the routes and obstacles these animals faced or how they used habitat configuration at landscape levels.



About 40 doe antelope have been captured and outfitted with GPS collars each of the last two winters to get a more detailed view of their habitat use and movements in relation to the larger landscape of the Northern Great Plains. Andrew Jakes, a PhD candidate at the University of Calgary, is conducting the work which is funded by a number of governmental and non-governmental entities.

The pronghorn are captured on their wintering areas near Malta and Glasgow, MT by Quicksilver Air, a crew that specializes in capturing animals using net guns fired from helicopters.



These guys are really good at this and it was a blast watching them work the animals. They were very good at minimizing the time spent with each herd and would capture an individual quickly and have it up and running again soon after the initial capture. In the photo above you can see the orange net covering a doe antelope and below is that antelope being released a few minutes later.





Below is a map of the capture locations in Valley County from February 2010. The pronghorn capture photos above are of number 166 (the furthest south capture, just northwest of Glasgow).



Below is the location of the animals at the end of April. Notice that 166 was about 200 miles north of her capture location (Glasgow and Malta are located along the bottom edge of the map and the dark line through the map is the US/Canada border).



The collars have a VHS transmitter and a GPS receiver. The VHS transmitter enables us to occasionally check the location and status of the animals (as above) and the GPS collars store the location of the animal every 2 hours or so. Then in February the following year, the collar is programed to blow off the animal and the VHS enables us to locate the collar and get the stored location information.



The map below depicts the cumulative locations of thirty nine animals from Feb 2009 to Feb 2010.



It is amazing the amount of land these animals cover annually. I imagine that if we had this level of information for all the animals that spend their winter along the Milk River, this map would be even more impressive, but even as it is we will be learning a lot about how these animals react to changes and challenges in their world.

Andrew has agreed to provide me with information on 166 as he gets her location throughout the year and next year when we recover her collar we will be able to see her how she moved between those spots. Stay tuned.

Pronghorn 166 update

This is not pronghorn 166. She is much farther north than this pronghorn.

Pronghorn 166 was relocated in late May, still the farthest northeast of the bunch (click on the image to enlarge). She was originally collared just north of Glasgow in February.

Transitions

Nope, not turning into a butterfly. However, it might just be an apt metaphor for this blog as I am emerging from a self-imposed exile due to a few months of changes and general mahem. A forthcoming post will provide a fast forward through the last few months of events in photos, but for now here is a quick rundown - weekly commutes between Billings and Fort Peck, four hours one way through June; co-leader of a Montana Audubon bird tour to Westby in early June with Ted Nordhagen and a fine group of fellow birders; the rest of the week was spent leading field trips and doing one presentation for the Wings Across the Big Sky Montana Audubon bird festival in Glasgow; the next week the movers showed up and packed the house up, we sold the house and on Friday that week we bought another house in Billings (which is slowly starting to feel like home not just a vacation rental of some sort); the next week I attended a BLM wildlife biologist tour in Eastern Montana around Miles City while Laura arranged and unpacked to the best of her ability; followed by a week of training on the ins and outs of the Migratory Bird Treat Act in Cheyenne, WY. We are now settling in to our new house and we are still trying to find that box that has the salt shaker in it. Did I mention the floods?

Other transitions have occurred slowly over the last couple of years too, but the realization of their passage just became more apparently recently. It looks as if the "Ice" portion of this blog will not be represented much here any more. My time with Oceanites - the arrangement that allowed me the opportunity to visit "the ice" and along the way Patagonia - has apparently run it's course. I have been outsourced by grad students with better connections and more free time to spend away from work and home. I remain hopeful that somehow things might work out, but for now it appears that it is a rather distant possibility. I knew it was going to come to an end sooner or later but it still is very disappointing that the possibility is no longer perched in the not too distant future.

On the up side - I have a rather large new landscape to explore right here around Billings. The Mussleshell River watershed is probably one of the most out of the way places in Montana and I am looking forward to exploring the prairie and foothills in this relatively brand new landscape for me. The Beartooth Plateau and Yellowstone Park are only a couple of hours away, and the Pryor Mountains and the Crow Reservation are just to the south. The Crazies, Castles, Little Belt and Big Belt mountain ranges are all within striking distance. And the Yellowstone River is not that much farther away than the Missouri River was for me at home in Fort Peck (there are just a few more houses between me and the river now). We still miss our friends and we really miss our family, but we don't have to drive 20 miles for milk anymore (oh and there is this great barbeque joint just down the street).
So what do I have planned for Prairie Ice in the new future? Well, there are at least four book reviews waiting in the wings, I need to finish the story of Pronghorn 166 (and what a good story it is), and there are a few other posts lurking in the corners of my mind where they ran away and hid when I started writing this sentence.
So, if anyone is still checking in, there is a pulse.