Trail Camera Trials and Tribulations

Trail cameras, or camera traps as they are often called, are used for many purposes in the scientific community. Biologists use them in a variety of ways including to aid in observing wildlife activity, wildlife behavior, nest predation, developing population estimates, and even identifying how wildlife use different habitat types. Trail cameras are often used recreationally as well. People use them for fun on their own properties to see what wildlife are nearby, what pest species are coming around their house, and what’s eating their garden plants. Additionally, they are often used as a scouting tool by many hunters.

These cameras allow us to see a whole other side of wildlife – their quirky personalities, sun baths, eating habits, sleeping habits, and sometimes even their predatory hunts! Moments we rarely get to see unless we are extremely lucky. I’ve used trail cameras quite a few times, both for professional and personal purposes. My favorite images are those that are a sequence of photos showing an animal walking into the frame, turning their head to look at the camera, stepping toward it, and then the next few images are either into the eye of the animal, up the nose of the animal, or a combination of the two as they explore the trail cameras. Animals can hear the shutter of the camera lens, and see the glow from the flash, so they get up close and personal to investigate. Others will try to play with them. I’ve even heard several stories of bears picking them up, knocking them down, batting them back and forth between their paws and then tossing them down a hill! However, not all species react in a curious manner. Some see it as a deterrent and skedaddle as fast as they can when they hear the click of the lens or see the flash.

Within the OWCN, our mission is to provide the best achievable capture and care of oil affected wildlife, and trail cameras can aid us in accomplishing this in several ways, especially during inland responses. First, many of the species we encounter are nocturnal, meaning they are primarily active at night. However, we are often not approved for night operations during the first few days of a response. Therefore, trail cameras can be our eyes on the ground and allow us to observe what species are in the area when we are not present. Seeing what species are roaming the hot zone while we’re away, allows us to be more prepared for the types of species-specific equipment we might need including traps, nets, housing, and transport necessities. In addition to knowing what species are present, we also need to know if those individuals have come in contact with the oil. Thus, I wanted to know if I could use the trail cameras to aid in identifying whether individuals seen in the photos were oiled or unoiled. Despite my previous experiences with trail cameras, I had never used them in such a context, and therefore, I decided to launch my own study to determine if 1) I could detect crude oil on a dark colored animal during the day (such as a skunk), 2) if I could detect crude oil on a dark colored animal at night (such as a skunk) 3) if I could detect diesel #2 on a light-colored animal during the day (such as a light grey rabbit) and 4) if I could detect diesel #2 on a light-colored animal at night (such as a light grey rabbit).

Due to Covid, I conducted this study in my backyard in Sacramento using a remote-control car, skunk and rabbit pelts, wire, crude oil, diesel #2, nitrile gloves, Tyvek, t-posts and two Bushnell trail cameras. I have not yet finished this study, but I found the initial results interesting and wanted to share them.

As stated in the questions above, I had originally decided to run the study during the day and at night. I ran transects perpendicular to the front of two cameras at a distance of 1m, 2m, 3m, 4m, 5m, 6m, 7m, and 8m from the cameras. As it turns out, it was very obvious during the day if they were oiled or not, and I ended up with tons of photos due to the large number of transects.  I realized that I could pare down my transects and still get a lot out of the data. Therefore, I reorganized the study so that there were only three transects at a distance of 2m, 4m, and 6m from the cameras, and that the studies would only be conducted at night.  I eliminated the 8m transect because the pelts were not outfitted with a heat source and since the trail cameras are triggered by a combination of heat and movement the pelts were unable to trigger the camera at the 8m distance. Below are some photos showing the study design.

Study Layout (Video)

So far, I have conducted one study during the day, and two studies at night. We will focus on the two nighttime studies for this blog, so let’s test your skills! To conduct this study, I used chicken wire to create a mold. Then I placed the pelt onto the mold and attached the pelt to the remote-control car with wire. I then drove the pelt along the transect in front of the cameras at the 2m, 4m, and 6m distances. I started with 0% oiled, then 25% oiled, then 50% oiled, then 75% oiled, and finally 100% oiled. Each transect was driven at the different oiling percentages. Below, are photos of unoiled and oiled skunk pelts (with crude oil), and unoiled and oiled rabbit pelts (with diesel #2, and crude oil). Can you guess which are oiled and which are not? I’ve posted an answer key at the bottom so you can check your answers. Feel free to leave a comment on this post and let us know how you did!






As you may have experienced with the photos above, it can be difficult to tell what is oiled and what is not when looking at still shot photos of wildlife. Check your guesses against the answer key below. Was it difficult to tell which ones were oiled at the 25% oiling? If so, imagine how difficult it would be to tell if the individual in the photo was oiled if they had less than 25% oiling! Thus, based on these few trials, I believe that using trail cameras during a spill response is critical for providing us information on what wildlife are active in the spill zone. However, I don’t think we can necessarily rely on them to determine whether an individual has been affected by oil. Especially if it is a light product on a light species, or a dark product on a dark species, and they are 4 meters or further from the camera lens. I plan to run a few more trials so see if the I get the same results! If you have any questions, comments, or suggestions, please email me at


Answer Key:

A) Unoiled

B) Unoiled

C) 50% oiled

D) 75% Oiled

E) 75% Oiled

F) 25% Oiled

G) 50% Oiled

H) Unoiled

I) 25% Oiled

J) 25% Oiled

Reducing Wildlife Impacts

For my initial blog post (yes I admit being in absentia on this score), I thought this would be a good opportunity to talk about a component of oil spill response that to some degree hangs out in the background of OWCN, but can be especially important in certain types of spills.  It is the part of potential response involving “hazing and deterrents”, or as I like to call it – “Preventive Medicine” for wildlife in oil spills.
TWV_HazingAs the Hazing Coordinator, I lead the hazing and deterrence effort within OWCN.  Because of our expansion to include inland spills, the types of wildlife that we are now tasked with trying to prevent becoming affected includes everything from birds to pinnipeds, amphibians to bears.  In order to assure readiness to accomplish this task, we have expanded our core hazing team in both numbers and locations in the state, and have expanded the range and amount of equipment that is prepositioned for this task. We have incorporated a number of wildlife biologists working for The Institute for Wildlife Studies into this core team due to their extensive experience with a wide variety of species, both birds and terrestrial mammals.  I am also working within the Field Operations group with Scott and Kyra to more closely integrate hazing and recovery activities to better utilize personnel in the areas most needed during a spill. We are regularly consulting other individuals who do hazing and deterrence to get ideas, and are working to widen the group of tools available to us.

Over the past several years we have conducted a number of trainings of volunteers, contractors, and staff in hazing techniques and tools, resulting in a dozen core hazing team members that are trained to lead field teams, and many volunteers that are trained to assist in a hazing effort.  Besides teaching how to properly utilize the tools we have available, we also test or research the wide array of behavioral responses to hazing that various species might have.
TWV_TrainingIn association with keeping up with the latest techniques in wildlife hazing and deterrence, last month I attended the Vertebrate Pest Conference in Newport Beach to learn what techniques people doing non-lethal human-wildlife conflict management are using that could apply to oil spills.  Some of the techniques described in talks at the conference could be especially important for deterring terrestrial mammal entrance into spill zones, so they were of great interest.  I also presented a talk about OWCN’s mission and work, not only hazing but also recovery and treatment.  This was done with the goal of letting some of the other professionals there know that we could be resource for them in the area of research and collaboration, and to improve overall awareness of the important work that OWCN-affiliated organizations do throughout the state.

Finally, we are expanding our interactions with the UC Research and Extension Station network, whose personnel such as Terry Salmon and Paul Gorenzel really started the initial hazing team work with OSPR, and developed key protocols and references we use today (the manual they created can be downloaded here).

TWV_ZonEspecially on the terrestrial mammal side, personnel from the Extension service often have a lot of expertise with deterrence and hazing, and they have allowed us to utilize several of their facilities for equipment storage.  We are quite appreciative of their cooperation and intend to continue to develop the relationship to allow us to give “best achievable hazing and deterrence” so that ideally, care can be a less necessary part of the equation.

– Winston

Raptors, Mylar Tape, and Boats to Protect Wildlife in Oroville

A few weeks ago, several OWCN staff spent a few days in sweltering heat in Oroville, CA to assist with an interesting project. This project came about because of an accident at the Oroville Dam in 2009 and resulted in the entrapment of hydraulic oil behind one of the valves. Because of the severe draught that California is experiencing, the Dept. of Water Resources had to open this valve, but were proactive in helping to protect wildlife from oiling by having several people from the OWCN be on site when they opened the valve. So earlier this month, Tim, Stephanie, and I spent four days in and around the water just below the Oroville Dam to help keep wildlife from potentially getting oiled by hazing animals away from the area of immediate impact. We used a combination of several hazing techniques, including hazing from the boat, using stakes with mylar tape set along the shoreline, a realistic-looking owl with a swiveling head that fooled more than one person, and the occasional and very technical “get outta here!” yells. Our scaring tactics were successful in keeping several species away, including a persistent osprey, a family of river otters, and many mergansers. Multiple cleanup crews from NRC were also present during the project, which helped deter animals from landing in the impacted area. In addition, several DFW-OSPR personnel were on site to help oversee the placement of the boom to protect resources. Overall, the project was a great success, and no animals were oiled. We congratulate the Dept. of Water Resources, CA Dept. of Fish and Wildlife – OSPR, and the groups subcontracted (such as NRC and Syblon Reid), for a job well done!



Nancy taking down the owl


Tim, Stephanie, and Nancy looking for wildlife and hazing animals from the boat on a beautiful morning


Mylar tape and booms


Kyra’s land station from where she kept an eye out for animals swimming through or landing in the water


Various project vehicles and materials and the OWCN’s “MASH” (Mobile Avian Stabilization Hospital), ready for action


We were hoping the birds would be scared away by our “hawk”


NRC worker cleaning the  OWCN boat, the "Screaming Grebe"

NRC worker cleaning the OWCN boat, the “Screaming Grebe”