19 July 2019

First USFS Permit Carcass of 2019

The summer heat arrived slowly this year and it has been raining quite a bit in our part of the Greater Yellowstone Ecosystem. The grass is high, cattle are in forestry permits, and it’s a busy time to be a range rider. As noted in the last post, the highest number of bear mortalities related to livestock depredation occurs during the bear’s early hyperphagia period which is late July through the end of August. This is a highly efficient ecosystem and it would only take a couple days for a carcass to lose all signs indicating depredation. One of my jobs as the Tom Miner Basin Association (TMBA) range rider is to locate carcasses and notify livestock owners and managers as well as the TMBA. This ecosystem is highly efficient in disposing of remains and if not found early, it is difficult to determine the true cause of death. 

On Monday, July 8th, I was in the high country of the forestry permit on my way to check on a herd that had recently been moved to permit and was in the most remote permit location I monitor. It was early morning and past a salt lick area where the trail narrows quite a bit, two ravens disturbed by my arrival, took flight 50m ahead of me on the cattle trail I was using. It was too distant to see what they were departing from but bird sign is an indicator of carcass presence.  It soon became easy to see a cow carcass in the middle of the trail. After making enough noise to cause a general disturbance in the area, I investigated the carcass itself to take photographs and then surveyed the surrounding scene to make observations that would be helpful for the livestock owners and managers to determine if it required Jim Rost. Jim Rost is a wildlife specialist that works for USDA Wildlife Services and among other things evaluates carcasses for evidence of depredation. Without a confirmation from a federally employed wildlife specialist a rancher would be unable to collect compensation for losses from the Livestock Loss Board of Montana (http://liv.mt.gov/Attached-Agency-Boards/Livestock-Loss-Board).

The cow was incredibly bloated and demonstrated rigor mortis (postmortem rigidity) but there was no stench. The cow’s face was stripped of hide with fresh blood from below the eye to mouth and also under the jaw. An investigation of the scene indicated the cow had been drug to its current location from up the hill. I was able to note this due to obvious drag marks and also a path thick with carrion (blow) flies

Important factors to note for livestock owners/managers: location, cattle tag number, signs of trauma and state of surrounding scene. I used my OnX app to mark the location of the carcass so I could relay the UTM coordinates.

Important factors to note for livestock owners/managers: location, cattle tag number, signs of trauma and state of surrounding scene. I used my OnX app to mark the location of the carcass so I could relay the UTM coordinates.

Was it depredation?

From what I was able to survey, I did not believe I was looking at a depredation event. The cow's body indicated it had been dead far longer than the face had been stripped of flesh. My best guess was that this cow died of larkspur poisoning and its presence on the trail was the result of an opportunistic find by a bear. As range rider, I am not able to diagnose the cause of death and only gather enough information to  and as stated by the owner of the cow, “take as many photos as you can of the carcass from different angles, trauma, signs from the scene it has been moved by predators-more is always better.”

What about the carcass?

The carcass was in an awkward place. I was coming from the north heading south and the carcass lay where the east side was a downward sloping forested area towards a cliff area that was thick with secondary growth, obscuring visibility. On the west side of the trail it was an incredibly steep slope with soft ground and deadfall. The cow’s presence in the middle of the trail was awkward because of there not being a safe way around the carcass on either side. To reach the most distant cattle, I head to permit right before dawn which would place me riding through the carcass zone when bears would most likely be feeding on the carcass. Others that knew the permit area better than I recommended possible paths that would still put me fairly close to the carcass and as a result, several days passed before I was able to ride through that trail.

In years with good vegetation levels cattle often do not eat pre-flowering tall larkspur which is when it is most toxic. In years like 2019 with plenty of grass, consumption hits a high during the late flower or pod stage. Although tall larkspur is less toxic at this point, consumption is higher resulting in the same high levels of toxic alkaloids in the cow’s system. The the amount consumed for death varies from year to year and more information about this phenomena will be in the next post).

In years with good vegetation levels cattle often do not eat pre-flowering tall larkspur which is when it is most toxic. In years like 2019 with plenty of grass, consumption hits a high during the late flower or pod stage. Although tall larkspur is less toxic at this point, consumption is higher resulting in the same high levels of toxic alkaloids in the cow’s system. The the amount consumed for death varies from year to year and more information about this phenomena will be in the next post).

On Friday of that same week, the livestock manager of the herd that owned the dead cow asked if I wanted to join to check on the status of the carcass. We rode to the carcass at the hottest part of the day when bears were more likely to be bedded down. Strangely enough, even though the cow had been moved about 75m east of the trail by predators, the cow was not completely consumed. The brisket and udders are two areas that bears tend to consume first yet were present that day. The gut and hindquarters of the cow had been fed on which suggests wolf and/or coyote (Clucas, 2005). Of course, there may have been a bear feeding during this time but without a trail camera on the carcass, it is difficult to determine how many species fed on this cow.  

Notes on finding:

When I was evaluating the carcass on July 8th, a pair (cow/calf), bull and an extra calf showed up to the carcass site. The extra calf without a cow had matching eartags to the dead cow and I was able to move all four to the nearest herd after I finished with the scene.

It was determined that the cause of death of the cow was larkspur. I will soon post more information about native plants that may poison cattle such as larkspur in addition to details on noxious invasive plants on forestry allotments.

-Sabrina Bradford, Tom Miner Range Rider

 References

Clucas, J.L. (2005) A Field Guide To Predatory Animal Damage Identification. Hawk Haven Media.