Camera Traps & Killer Housecats

SciWorks Radio is a production of 88.5 WFDD and SciWorks, the Science Center and Environmental Park of Forsyth County, located in Winston-Salem.

Domestic house cats have an important role in our hearts and in their outdoor habitats. In general, one problem with habitat management is an incomplete picture of what animal species are present. One way to discover elusive species is through camera trapping.

To learn more about this, I spoke with Dr. Roland Kays, Research Associate Professor at NC State University, and Director of the Biodiversity Lab at the North Carolina Museum of Natural Sciences.

We use a lot of camera trapping to collect data on where animals live. And you can use this to learn about the type of habitat they need, how they interact with people, and especially how do people impact where the animals live. So by running camera traps and seeing, oh well, we get a lot of a certain species here, a lot of pictures and we get zero of them over here, we can compare those places and see what's different about that and what type of habitats do these animals need to survive?

Camera trapping involves mounting a motion-sensitive camera to a tree, and leaving it for a while to collect images. It's not a new concept.

Camera trapping has been going on for almost a century now. A hundred years ago there was a guy named George Shiras who would sneak up on animals and take pictures. They were some of the first wildlife pictures ever. The public was just fascinated with them. What he realized is that he could actually leave the camera there and tie a string to some bait. When the animals would pull the string, they would take the picture. These were the big, full format cameras on giant wood tripods with cakes of magnesium powder as flashes so when it would go off there would be an explosion basically. It must have totally freaked the animals out. But he got these really nice pictures. Today we've got digital cameras with infrared flashes so the animals aren't disturbed. We set hundreds of cameras and get millions of pictures.

Dr. Kays collected data for his recent publication from 485 volunteer citizen scientists, people like you and me, who set hundreds of camera traps over six states.

We've run cameras from South Carolina up to Maryland in 32 different parks. That was volunteer citizen scientists working with us, going into these parks, taking hikes, running cameras.

Camera traps were also deployed in backyards and urban wooded areas around Raleigh. All this because cats . . . 

Domestic cats in the United States kill many billions of native birds and mammals. Which just adds up because there are so many cats in the United States. We wanted to know where this is happening. Because if the cats are going into the nature preserves and killing animals there, that's a much bigger problem than if they're going into their backyard or the local urban woodlot where they're probably killing local urban species. And so, this data set, all these cameras, we knew whether or not they detected a cat and how many cats they detected. What we found was virtually no cats in any of the nature preserves. Half of the preserves had zero cats, some of them had one single cat, and some of these were really urban. What we did find was a lot of coyotes. What we think is that the coyotes are basically protecting these parks from these invasive cat species by either killing the cats or making the cats too afraid to go in there in the first place. We get 300 times more cat activity in the average backyard, but very few coyotes in backyards. And then if you go into the small urban woodlots, that's where we would find both coyotes and cats living together.

Thanks To Dr. Kays and his army of citizen scientists, we now know that cats, while responsible for considerable carnage, have almost no impact on protected areas. However, the usefulness of camera trapping goes far beyond keeping tabs on our family pets.

What we want to look at is . . . not only about the cats but about the other animals that live near us. What are those animal communities like in suburban areas and in rural areas and in more wild areas. We want people to run cameras at different distances from the city center and also in different habitats. What are the animals that are living in the backyards, in the woodlots, in the golf courses, in the cemeteries, in the more open areas, and also in the forest? We'll actually be going down to Panama later this year to look at an area where coyotes and a species of South American Fox are colonizing new land at the same place at the same time. You'll probably never see one with your own two eyes, but you leave the camera up and you can get the data and the pictures.

This Time Round, the theme music for SciWorks Radio, appears as a generous contribution by the band Storyman and courtesy of UFOmusic.com.