discussion / Camera Traps  / 12 April 2021

Camera traps in the tropics: no detection of wildlife visits

Hello everyone,

I'm Patrícia and I'm currently working as a reseach assistant in Príncipe island. One of my tasks here is to use artificial nests to understand how introduced mammals (i.e. Mona monkeys, african civets, rats, feral cats, etc) might be impacting a critically endangered endemic bird species. We are placing camera traps facing the nests to record visitors and predation events, however, the camera traps are not working properly. They take photos of us during instalation and when we go back to get them but not of anything in between (and we know something should be recorded because eggs disappear, nests are found on the ground, etc). 

Does anyone have an idea of why this can be happening? I thought it might've been due to camera or nest position (i.e. exposure to sun so the difference in temperature might not be enough to trigger the camera) but cameras and nests are in shaded/not under direct sunlight areas. I also put the sensor on high.

We are using the Bushnell trophy cam HD model 119776

Thank you!

    That must be frustrating! My apologies if this too obvious of a question, but is it possible  that the most common nest predators are ectothermic, such as a snake?

That is an interesting problem! And intriguing idea from @russvanhorn .

How far from the nests are you placing the cameras?

It is possible that the detection pattern of the cameras are to coarse for the size of the nest predators. 

Could you setup continous video like a cctv system on one or two nests to learn what is causing the predation?



Do you have time to test whether the Bushnell cameras detect those species in another place? For example, with a bait at a range of distances from the camera in a place where you know there are monkeys/civets/cats/rats. Or test the camera on domestic animals - such as Peter Apps' great camera tests:




If the camera is working okay, then consider a different placement - different distances and angles.

Another option is to set the camera trap to capture time lapse images or "field scan" setting in the Bushnell. The quickest interval is 1 min, so you may not catch the animal in the act with this option, but you might be able to record when it happened. 

Let us know how you go.



This sort of problem is tricky to diagnose without seeing the actual set-up.

How often has this happened, and at how many sites ?

The first thing to check is that the Camera Mode setting is on the default of 24 hr, not day only. Bushnell have both a Mode and a Camera Mode setting just to keep things interesting !

I cannot find a trigger speed specification for that model, but depending on how you have the camera aimed relative to the nest boxes and the direction the predators come from, they may be getting into th box during the trigger time and then out again and away during the trigger time.

Keep in mind also that all camera traps are really bad at detecting animals moving directly towards them or away from them.