The use of camera traps has been a common practice in both research and hobby for the last few years. Also known as trail cameras, trap cameras let you take pictures and videos of animals by the use of a passive infrared heat and motion detector. In scientific studies, camera traps are commonly used in monitoring mammals and birds as amphibians and reptiles are difficult to capture.
Camera Trap Technology
Camera traps use a type of sensor known as a passive infrared (PIR) sensor. The PIR sensors are effective at identifying a difference between the rapid change in heat and ambient background temperature as a result of an animal’s presence. Therefore, PIR sensors detect heat from the surface of objects and hence temperature itself should not affect it.
A PIR sensor comprises of two major components including pyroelectric sensor and Fresnel lens. The Fresnel lens aids in focusing incoming electromagnetic radiation onto the pyroelectric sensor to allow the camera to capture an image or begin recording. As such, camera traps are triggered as soon as the electrical current in the pyroelectric sensor attains a particular threshold.
However, there are various manufacturers who use different pyroelectric sensors and Fresnel lenses. This means that different camera traps have varying efficiency when it comes to capturing different species of animals just as the temperature of species vary.
One part of the sensor is an infrared filter which controls the light that goes to the pyroelectric elements to wavelengths of about 6 – 14 μm. This reduces the chances of false triggering of trap cameras as animals surface temperatures occur at this range of wavelengths. Camera trails capture colored images in the day and black/white images at night, thanks to the infrared flash (invisible to humans and wildlife).
It’s important to note that moving objects that may be warmer or cooler than the background object e.g. spider webs and plants may result in triggering of the camera especially when the camera is too close to them. Also, if it is exposed directly to the sunlight, it can show a similar effect.
It is, therefore, recommended that you should mount your camera on a strong pole or tree and ensure a clear line of sight and completely sheltered from the sun. Note that patchy sunlight can trigger the camera as it is highly sensitive to rapid changes in temperature as well as moving vegetation. Therefore, perfect positioning will not only minimize the false triggers but will also save your batteries and space for when the animals arrive.
Battery Choice Is Vital!
Battery and power are a major factor to get the most out of your camera trap. A surge of energy is a need to help turn the camera on and record a video or take a picture. The battery choice may affect how you capture animals; The IR LEDs to be specific, are the biggest power draw on any camera trap. Poor batteries may result in inefficiency as the camera may be triggered to capture images during the day only as the power is inadequate to trigger the camera at night.
Normally, a photo uses less energy from the batteries as compared to a video. Therefore, it’s advisable that you should equip the camera trap with the maximum amount of batteries the camera can hold. Additionally, lithium batteries work better than alkaline batteries.
You may need to avoid Duracell batteries as these hold high internal resistance and some may have a relatively low energy capacity which means less efficiency in camera traps. Lithium batteries are considered ideal as they show a big difference; they have an energy capacity of approximately 2900mAh or even higher depending on the manufacturer. On the other hand, alkaline batteries may vary in energy capacity as they range from 1700-2850 mAh. A camera trap works well with at least 2500mAh especially if the amount of LEDs in the camera are high.
Camera trails use digital technology which means that you can view recorded images and videos in an in-built SD card. What’s more, they use cutting edge technology which implies that the images are often hi-res that range somewhere from 3mp – 12mp. They are a valuable asset to a wide range of professionals including wildlife researchers, wildlife enthusiasts, game ranger, anti-poaching units and even hunters.