Summertime Brings Changes to the Canyon Wildlife

Three trail cameras continue to film wildlife and human activity in an undeveloped 88-acre canyon. This canyon is ideal for observing wildlife responses to  changes—it’s surrounded on all sides by businesses, roads and homes. For more than three years the cams have recorded how the suburban canyon wildlife reacts to the pressures of urbanization and a shrinking habitat.

A mountain lion visits the canyon on a weekly schedule. He was first filmed months ago, patrolling the trail in the early mornings, long before the joggers, walkers and dogs are out. The main trail camera is in the perfect spot to record him hesitating at the trail junction before continuing on his way. He usually stops for only a second or two, scents the air and scans the trail for potential threats. This boy is not the only mountain lion who regularly visits the canyon. A female is also an occasional visitor. In addition to the two pumas, the canyon appears to be hosting an increasing number of wildlife.*

A surge in canyon wildlife

After months of animal absenteeism, the canyon appears to have once again become a popular wildlife hot spot. Since late spring, the memory cards are filled to capacity with vids of dusky-footed wood rats, mice, rats and rabbits—magnets for predators. There is also a noticeable increase of deer hanging out in the canyon, observable with and without trail cameras. When walking slowly and quietly, you may catch a glimpse of deer off the paths munching on the vegetation. It is not a mystery why the mountain lions are drawn to the canyon—they follow the food and venison is their top menu choice.

For close to a year the trail cameras filmed only a few wild animals. The timing of the decrease of wild animal sightings coincided with the increase of people who discovered the little suburban paradise during the pandemic. Instead of the usual canyon wildlife, the memory cards were filled with videos of people, bicyclists and hundreds of dogs, many off leash, racing through the sensitive habitats.

After a long and painful year, we are finally on the other side of the pandemic. It appears that the unfortunate trend of dwindling wildlife is slowly reversing. Although many hikers and joggers still favor the trails, the cameras are filming fewer of them. Additionally, sightings of bicycles and off-leash dogs have decreased. This shift in human activity may be one of many reasons animals are either increasing in the canyon or making more appearances.

Mountain lions

Although the two lions, a male and a female, have not been filmed together, they do seem to time share the area, walking the same trails on different days. Pumas are territorial—especially the boys who have zero tolerance policies for other males. They compete for a limited number of females and food. For obvious reasons, males are at times more accepting of girls and it is not unusual for their territories to overlap those of females.

Mountain lions, like other members of the Felidae family, communicate a broad range of information about themselves and they also delineate their territories by marking. These include scraping dirt into piles with their back paws and then urinating or defecating on them and scratching objects, such as trees and logs. Although I searched for evidence of puma territorial markers, I have not found any in the vicinities of where the cats have recently been filmed.

Mountain lions are foodies—they love venison and for the last few months there has been plenty of it in the canyon. On an average, pumas usually take down one deer a week. It is not devoured in one sitting—one deer can feed a lion for a few days. On an average, they eat about 8-10 pounds of meat a day. The carcass is cached, covered with leaves, brambles and debris. Mountain lions do not usually travel too far from the carcass, that way they can snack on it when they’re hungry. The carcass feeds more than the lion—other opportunistic scavengers and predators, such as raptors, coyotes and smaller animals benefit from successful mountain lion hunts.

Bobcat sightings

The canyon bobcats are a continual source of entertainment, especially because I recognize a few of the individual cats. During the last few years, I have sketched out the placement and shapes of the spots on their front legs.

Patterns, placement and shapes of spots that are on the front legs of 3 different bobcats

Although, it appears that parts of the canyon are the core home ranges for at least two female bobs, a couple of males have also been filmed occasionally in the girls’ core zones. Core ranges are located inside much larger ranges. These smaller core zones include successful hunting spots, numerous shelters, water sources, and safe areas for birthing and raising kittens.

The two canyon girls might be related. When bobcats are 9-10 months old, they leave their mums to seek out their own territories. Males disperse further than females and have larger ranges which often purposely overlap the ranges of girls. Depending on available terrain and other critical necessities such as food, water, shelter and safety, the girls may stake out territories near their natal neighborhoods. Sometimes the outer reaches of their ranges are adjacent with their mums. Like most felines, bobcats live solitary lives, hunting and raising their young alone.

Bobcats don’t just hang out in their core home ranges—they patrol their whole territories. The canyon bobs often cross the dangerous road that borders one side of the canyon, accessing protected open space to hunt and possibly fraternize with the opposite sex.

At least two batches of kittens have been born, nurtured and raised in the canyon this year. Typically, litters start out with three kittens, but it is not set in stone. Unfortunately, it is rare for all to survive. Despite vigilant mums, it is a dangerous world for youngsters. Note the smallest kitten on the far right in the first video. Only one eye reflects light back into the camera. This little one may have a serious problem which may negatively impact the odds of successfully surviving into adulthood.

They are so cute bouncing down the trail.

I hope the trend the cameras are recording of an increase of wild animals in the canyon continues. Although there are many factors contributing to this latest shift in occupancies and visits, most likely it’s not a coincidence that the decrease of people, bicycles and off-leash dogs is making a major impact on the wildlife.

*You will note that the date stamp on some of the vids says the year 2020 instead of 2021. Unfortunately, one of the cameras does not display the date correctly and keeps defaulting to the wrong date.

Marilyn is a certified cat behavior consultant (The Cat Coach, LLC). Not surprisingly, she’s fascinated by feline behaviors. This started with household cats and then after witnessing a puma being killed a few blocks from her home in the suburbs, expanded to include local mountain lions and bobcats. A few years after the tragedy, she joined the Bay Area Puma Project/Felidae Conservation Fund, maintaining trail cameras, writing and helping wherever she can. She is focusing on how urbanization is affecting apex predators’ behaviors.

She is also an author and educator. Her book Naughty No More! focuses on solving cat behavior issues through clicker training, environmental changes as well as other positive reinforcement techniques. She gives presentations throughout the United States as well as writes columns and articles for a variety of venues. She is also frequently interviewed for print and on line publications. Additionally Marilyn is a frequent guest on television and radio and has appeared, along with her Bengals and Savannah Cat on Animal Planet, CBS, ABC, KGO and others.

Join Marilyn for lively discussions about all things feline on her Facebook page.