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 firstname.lastname@example.org.
C) 50% oiled
D) 75% Oiled
E) 75% Oiled
F) 25% Oiled
G) 50% Oiled
I) 25% Oiled
J) 25% Oiled