CRP Mountain Lion Study
Thinking Outside, With Paws!
This week we were joined by Mountain Lion Foundation biologist, Diana Lakeland, who will be providing advisory support on camera placements and how to look for lions on the Preserve. With a grant from the Sacramento Zoo, the Mountain Lion Foundation has provided us with ten cameras to be able to expand and continue the BLM’s mountain lion camera project. We’re glad to have her aboard!
We started checking cameras early in the morning and by mid-morning there was a substantial wind blowing. The Weather Service estimated winds would blow at 50 to 60mph! By the time we got back to the Visitor Center to check our images, it was practically gale force outside, dry and windy with the air becoming almost misty with dust and soil becoming airborne from the surrounding dry and disced agricultural fields. Discing happens in the fall, where a tractor pulling a row of large metal discs turns up the soil, aerating and distributing fallen vegetation to prepare the field for seasonal flooding to welcome the incoming sandhill cranes and migratory waterfowl.
At the first camera we noticed one large, grey feather that looked as though it had been chewed on. This can be an indicator of a carnivore plucking the feather from the bird carcass and leaving spit behind, having chewed and pulled the feather out of the carcass. The quill was also broken off, indicating again, perhaps a carnivore had made a meal of this bird. We weren’t able to identify the feather and we did not find a carcass but maybe a heron? We also found many tracks just south of this camera along an old fenceline, including deer, coyotes, otters and raccoons all navigating the barbed wire obstacle by either bounding over or crawling underneath.
We also investigated an area where it looked like a barn owl carcass had previously been devoured, likely by a larger owl or raptor deep in a heavily vegetated area with large oak trees and cottonwoods. Barn owl feathers hung and trailed lightly from a perching spot that had large white scat spots just below it, indicative of a raptor, and we found an owl-sized spinal column, largely intact, that could have belonged to the barn owl.
Moving to the next camera, we found a very large river otter latrine with fresh scat. A latrine in the wildlife sense is where an animal or several use a common spot repeatedly to defecate. Many animals employ latrines, including bobcats, voles, otters, raccoons and even coyotes. It’s a way to claim territory and announce regular presence along a well-used travel corridor or near a den. Fresh river otter scat can be red or orangey in color from the undigestible red and orange crawdad carapaces that move through the otter’s system. As the scat dries and is exposed to sun, it becomes darker and the crawdad remnants bleach white.
The next camera is the site of a telephone pole that’s been used by bobcats for several years to scratch. In fact, it looks like the utilities folks have even applied some creosote to discourage the kitties from scratching but they persist! There are fresh scratches on the pole. And Diana even posed next to some scratches that are rather high up on the pole, like mountain lion high. Diana is over 5 feet tall and you can see these scratches were made well above her head level. It’s also true that bobcats climb trees and can back down to the ground. Maybe this could have been a bobcat but there were some pretty large scratches! It might not be surprising if a mountain lion made a few scratches on the pole to let the bobcat know who the big guy in town is.
We also watched what we thought was a young buck moving through the big trees and heavy hanging grape vines, using his quiet, jerky, paced alarm walk to move away from us. Deer use an alarm walk to size up perceived danger while moving away from it and determine when the distance is safe to break into a run. This fellow was back-dropped against the sunlight and we never got a great view of him but walking back to our vehicle from the camera we came upon what is likely some buck scrape. Deer are just coming into the rut season on the Preserve and already on camera we’re seeing 4-point bucks following closely behind as many as four does at a time. Also, does are alarming more frequently on camera as the season changes which could either mean a mountain lion is scenting the area or they’re running from amorous bucks! Bucks are starting to drop signs and scent that marks their territory and to claim their harems. This could be where a buck stopped and made his mark in the loose dirt, maybe prompted by the scent of does or another buck in the vicinity. Bucks can make scrapes both with their hooves and their antlers.
A large part of our discussion for the day was how mountain lions might move through the Preserve and the virtually endless multitude of corridors they could use to create and maintain the secretive cover they’re known for. Most of our cameras, ten provided by the Mountain Lion Foundation and two supplied by the Bureau of Land Management, are deployed on choke points that were established in 2014 at the beginning of the project. Choke points are corridors and pass-throughs on the landscape that are defined by geography – water, roadways, dense brush, steep hillsides – and are logical pathways for wildlife to travel using the least amount of effort. The discussion evolved to examine the fact that our cameras have largely been deployed in the same spots with no success at capturing an image of a mountain lion, even though there were several reputable sightings of lions earlier this year. So, thinking outside the box, we are now planning to move several of the cameras to areas that have good cover for lions and other wildlife but may not be directly on a roadway on the Preserve.
One camera in particular is deployed along a well-used road by utilities, farmers, Preserve staff and volunteers through a remote area of the Preserve. This camera regularly gets a lot of deer passing both east and west as they move by the camera. It may be that this road is so well used, a lion wouldn’t set paw to it and so the deer have made this choke point one of their regular routes because it feels safer. We are considering moving the camera a bit to the northeast, just off the roadway but along a break area that borders an agricultural field parallel to the road. Easy walking for a lion, with cover and the ability to see a distance out across the field. We’ll need to sink a post at this location and then drill several holes into the post and mount up the camera. Then we’ll see what we get!
How mountain lions use flat lands such as the Cosumnes River Preserve is much different compared to how they use the foothills and higher elevations. On the Preserve, there are no heavily defined topographic features that a lion might avoid as being too energy consuming, like steep cliffs to climb, or be drawn to for hunt opportunities, like deep ravines. The relatively flat topography with riparian, open savannah and deep oak forest cover provides a wealth of opportunity for a lion to pick his or her way through the cover while looking for deer and determining whether this is suitable territory. Also, remembering that every mountain lion is an individual, there’s just no telling what might draw a lion to head right or left when they come to a fork in the trail. Smells, sights and sounds may determine whether there is a hunt opportunity, a mate nearby, human danger in the area, or a restful spot and lions on the Preserve must rely on the deep cover available there for protection.
It’s not easy being a mountain lion on the Preserve but we’ll be switching up the camera action to see if we can catch one walking by!
Final Note: We were also surprised to see a bald eagle soaring over the Preserve in a thermal with 5 or 6 turkey vultures, a red-tailed hawk and a merlin. All of these species soared peacefully in the same thermal column for ten minutes or so, and the eagle gained in elevation the whole time, soaring higher and higher. He or she eventually glided off to the northeast, likely either in search of another thermal to gain momentum or to hunt. Often, soaring birds like raptors will use thermals as a method of least energy expenditure to get to hunting areas, capture prey, and then catch a thermal to ride back to a safe place to eat their meal. Birds are very intelligent! Next time you see a soaring raptor, remember that they’re not just kicking back. They’re thinking about where they need to go and how they’re going to get there!
Blog by Erin Hauge
Some of these photos below were taken while the lion camera crew was hard at work checking cameras – some tracks and buck scrape, bobcat scratch on a telephone pole and some scratches much higher on the pole as well! Also some scenes from remote areas on the Preserve near where current lion trail cameras are deployed. And some of these photos are courtesy of the Bureau of Land Management, views of the critters our cameras are capturing!