Saturday, August 28, 2010

Bobcat Collars: FAIL

After finishing a study site just moments before the sky began to spit out teardrops, Bobbie and I happily climbed into the truck to head down the mountain. Just as we crossed onto the paved part of the road (which means home is close because one can drive fast!), we changed one of the channels on the receiver to see if one of the bobcats was in the area. Hearing only static, we were about to turn off the receiver (the signal comes via GPS through the collars on each cat. An antenna on the collar allows us to know if we are within two miles of an animal. We have a hand held transmitter, and also one glorious magnetic antenna that sits on top of the truck and allows us to cover ground more quickly), we heard the double clicking signal. The signal emits a heartbeat-like beeping on a live animal, but a rapid clicking serves as a mortality signal. My heart sank as I heard my first mortality signal, and we began a triangulation to determine the relative location of the cat. A triangulation is putting three compass bearings and their respective UTM's into the GIS for a fairly accurate location for an animal. We take the hand-held antenna and point it in the direction that the signal is loudest, narrowing it down to a directional line. That line is used for a compass bearing, and we then travel ninety degrees in a circle (hopefully!) to determine yet another bearing. It can take six or seven times to get enough points at varying angles so the GIS will determine a location (via computer). That being said, Bobbie and I didn't have a computer, so we tried to determine a relative location for our cat. We then grabbed our gear and headed out to find the body. Unsure of what we would find, we had our bear spray in case our cat had been killed by a bear or mountain lion. The telemetry led us into a mature forest with lots of fallen logs... sadly a place that a bobcat would live, and also choose to die. We commenced our search, but we very quickly ran into a problem: the signal was everywhere. Telemetry is very simple: the closer you get to your target, the louder the signal. Ideally, an unmoving object presents a fairly easy target. However, our deceased animal's signal was not only getting louder, but it was louder a hundred yards across the trees. We searched in fallen branches, in stumps (I did work for almost ten minutes hacking into a cedar log. You actually cannot hack into a cedar log.), and up in trees for any sign of a carcass or collar. The pieces might not have been together, so we searched for anything. As it started to rain, I heard my first elk... and it is a strange sound. Way up on a hill, we could hear a startled and irate bull elk snorting at us repeatedly. After adjusting to the sound, we continued to curse and scratch our heads over the strange signal. We found traces of what we thought was bobcat and deer hair, but nothing else. After an hour, we went home soaking wet, empty handed, and disappointed.

The rest of the week revolved around finding this dead bobcat. We determined that the signal must be bouncing off of the many ridges of the mountains in this one area as well as the river running through the valley. Bobbie and I spent the next two days hiking for the cat with three paws. This bobcat was caught in a furbearer trap this past December (a conibear trap), but escaped only because he chewed his own paw off. I digress to marvel at the fierce instinct of survival this cat had to chew off his own paw. Our search for this amazing cat, whose fate was still indeterminate, led us to a cliff over the river:


The signal was leading us down into the valley. The river running through the valley was swift, with picturesque rapids and contrasting clear, still moments on the rocks. From the cliff we leaned over we could see how deep the river was in some parts, and there was one rock in the center of the riverbed that was easily four times the size of my car, and much taller, that was covered completely by the crystal clear water. The path down, however, was very down, and the slope was covered by rocks that had fallen off the cliff in an avalanche. Making our way down, we determined that not only was the signal inconsistent, but it was leading us across the river.

Crawling down to the bank, we looked at the water, then at each other, and Bobbie said, "I'm game if you are." Pumping myself up to cross this river was completely crazy! We debated leaving on our boots, but we found a more shallow area to cross (only thigh high) and decided to take off our boots. I know I definitely did not notice how cold the water was, as I was intent on not losing my balance over the sharp and slippery rocks that were urging the water to rip me off my feet. Don't get me wrong- we weren't going to die, probably- but I don't know anyone who is relaxed about getting swept down a fifty degree river with expensive equipment in their pack.


Bobbie snapped this picture on the way through the river the second time. She snapped the pic as I was lifting my right leg to take another shuffle, but I almost lost my balance. The other, and more dignified photo, shows me with both arms going into the water and trying to straddle the rocks with four limbs and keep my footing.


The journey in between these photos gave us new insight to the term "going in circles," because that is exactly what we did! The signal got loud, then faint, then took us left, then up, then right and down. We found wild strawberries, moose bones, and I heard my first osprey. We had just decided to give up, and I had long ago determined that I had no idea where we were in relation to the river, when we rounded some trees and came upon the giant rock we ate lunch on. We had come full circle! This is not good, because the whole goal of the day was to find our deceased bobcat.

Getting back to the truck, we discussed our options, concerned we would have to fly a helicopter to find this cat (no joke). The next day, however, the signal was in a different location entirely. From the road, the signal was coming and going. That usually only happens when a bobcat is active. Active = Alive. Hmmmmm. This cat, M6, was one of two cats wearing a different brand of radio collar. The next day we decided to search for the other collared bobcats to see what their signals sounded like. Driving the roads, we found each cat, and each signal was a live signal, except for M5. He, too, had the same mortality signal, and he is the other cat with the other brand of radio collar. The collars have a live signal, a mortality signal, and a recovery signal when the battery is dying. Nature is unpredictable, yet the coincidence of having two cats dead within 48 hours, combined with the inconsistency of the signal strength, pointed to one very enlightening fact: our cats were alive! Poor M6 had been moving in the woods for two days trying to get away from the crazy beeping ladies, and we had been tailing him the entire time! After our excursions, we managed to discover that the mortality signal and the recovery signal on the transmitter is only slightly different (why this was highlighted in a very tiny footnote instead of a bold headline in the manual is beyond me).

Long story short, no cat was harmed in the making of this adventure. The company who makes the collars that failed after only four months is still intact, and we are currently wrapping up the field season by trying to catch these bobcats so we can retrieve the information on the collars!

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