D

Over the last decade, millions of people around the world have become aware of the camera trap. The candid images and videos that camera traps produce have been featured in countless documentaries, are widely shared on social media, and have been the focus of hugely popular citizen science projects. Less well known is the fact that the camera trap has a long history that extends back more than 100 years. Over this time, they have gone from being an experimental technology, used by just a handful of people, to a commercialized technology being used by many thousands of photographers, hobbyists, hunters and biologists.

The modern camera trap is simply a digital camera connected to an infrared sensor which can "see" warm objects that are moving, like animals. When an animal moves past the sensor, it causes the camera to fire, recording an image or video to the memory card for later access. Camera traps can be left in the field to continuously watch an area of habitat for weeks or even months, recording the rarest events which occur in nature.

This can include everything from a big cat patrolling its territory to the raiding of a bird's nest by a hunter that targets baby birds. Camera traps are "wildlife friendly", in that they cause little or no disturbance to wildlife. At the same time, they produce permanent and provable records of animals.

Camera traps provide data on species location, population sizes and how species are interacting. They also help us to understand how humans interact with other forms of wildlife.

The development of networked camera traps, capable of sending images over phone or satellite networks in near real-time, has provided a new tool to protect wildlife from illegal hunting. New software tools and statistical models are also making it much easier and faster to obtain high-quality information from the thousands of images that camera traps can quickly generate. This is improving our understanding of human impacts on wildlife, and helping land managers make better decisions at both small and large scales.

Despite the great potential of camera traps, there are a number of significant challenges involved in working with them. Small animals are less likely to trigger the cameras, and it can be difficult to identify similar-looking species or specific individuals from a photo or video. One of the main challenges is processing the millions of images generated by cameras.

"People are facing major bottlenecks when it comes to turning images or videos into structured data," says Zachary, a wildlife ecologist. The key to addressing this challenge lies in building open and collaborative platforms, and efforts are already underway. Then, the potential goes far beyond that. With such platforms, conservation efforts will follow.