Offal Wildlife Watching: Camera-trap monitoring of hunter provided carrion

Who:

We asked deer hunters in Minnesota, or those that participate in deer camps, to place remote cameras on gut piles from freshly field dressed deer. Volunteers left their cameras to capture pictures for one month to capture all the scavenger species that used the gut pile.

What:

The purpose of this research is to better understand what and when species use deer gut piles provided by hunters across Minnesota. Minnesota offers a unique opportunity to look at this across four different biomes and a large metro area (Click image to enlarge). These areas have differing topography, vegetation, and human land use. All of these things are likely to influence the different scavenger assemblages found in each area. There are also several methods of hunting such as archery, rifle, and shotgun that may influence where a gut pile is located, and which species visit.

Why:

Scavengers have been shown to obtain high quality food from carrion without using the energy needed to capture and kill prey. A large amount of carrion available to scavengers is provided by apex predators, such as wolves, or the natural death of prey. Likewise, at certain times of the year, hunters can provide a significant source of carrion in the form of gut piles. The resource pulse of gut piles that hunters provide generally occurs over a small area and short period of time. This pulse represents a large input of gut piles into the ecosystem from animals that would otherwise not be available to scavengers. Carrion pulses have the potential to reduce predation on prey species by providing a less risky meal for predators. Alternatively, predators that consume carrion may also increase predation pressure on prey populations in the same environment when the carrion pulse is depleted.

Since gut piles are provided by human hunters, the suite of scavengers and time that animals scavenge is likely to differ from carrion left by predators. Mere human presence on the landscape may attract wildlife. For instance, similar to their response to wolf activity, ravens respond positively to the sound of gun shots, because it means easy food. Large carnivores such as gray wolves and bears may also be drawn to hunter gut piles.

Questions

Is there snow?

Snow and cold temperatures can affect the detectability of food resources. Offal piles are no different. We want to know if there is snow on the ground so we can relate that later to the species that are visiting the offal at that time.

Is it a bird or mammal?

When a highly nutritious food source such as hunter provided offal are abundant on the landscape, different species guilds are often observed at the same food source. For this question, volunteers will be determining if the scavenger species is a bird, mammal, or if both are present at the gut pile.

What species use offal?

Minnesota is unique in that it has four distinct biomes. Each biome supports different vegetation communities, human land use, and consequently, different scavenger species. This question will help us determine the species that are recorded at hunter gut piles across the state.