We are conducting surveys, monitoring, and research on cougars (puma, mountain lion) on the Ladder Ranch in south-central New Mexico. Here, cougars are of particular interest given their effects on state-endangered desert bighorn sheep and other valuable big game. These projects are also resources for training and education, most notably through the Cougar Field Workshop.

Friday, December 22, 2006

Yesterday at approximately 07:45 I received a mortality signal for one of our bighorn ewes, frequencey 150.700. Unlike the mortality farce in October, this was no trick of radio frequency overlap. This ewe was indeed dead, preyed upon by a cougar. By 12:15 I had located the carcass. At this particular location there was very little surface soil and it was difficult to find tracks of any kind. I was able to determine that the ewe had been attacked approximately 100 meters uphill from the cache site and then drug downhill by the cougar and deposited beneath a mesquite. Cougars typically cover their prey with soil, sticks, and organic debris, often beneath a low tree or shrub. In this case, there was no surface material available to cover the carcass. I set a remote camera in the evening and this morning retrieved the photo above. It is most likely that this cougar came onto the mountain from the river area, as I have recorded multiple sets of tracks coming up from the river previously (see previous post for 20 November). As I was investigating the site today, I could hear the crack and boom of bighorn rams competing for ewes on the mountainside above me.


Friday, December 08, 2006

It seems we have identified a relative hot-spot of cougar activity. This is the first time we have found cougar sign in the same place twice. I also found a scrape about 30 m from where this photo was taken. A scrape is a site of chemical communication where male cougar create a small mound of soil and organic matter and a 15 to 25cm depression in the soil and debris by scraping the surface of the ground with their hind feet. Frequently, they then defecate and urinate on the mound of debris. Typically males make scrapes throughout their home range along travel routes and near kills. An Idaho study found that cougar scrapes were more common along home range boundaries (similar to what has been found for tigers, jaguars, and leopards). A study of cougar scraping behavior in the San Andres Mountains of New Mexico by Ken Logan and Linda Sweanor found that 26 to 33 percent of a male's scrape sites were shared with one or two other males.


This striped skunk (Mephitis mephitis) managed to get to the water before it froze. These small carnivores are surprizingly abundant in the study area.

Temperatures have been dropping into the teens here at night and the water in the drinkers has been freezing. Here you can see two mule deer (Odocoileus hemionus) making a disappointing discovery as they find their water frozen.