discussion / Camera Traps  / 22 August 2022

Camera trapping in the tropics

Hi everyone! New camera trapper over here! I have some questions specific to camera trapping medium-large mammals in the tropics, especially rural areas of Central America (Guatemala or similar location):
 

  • Are predators/camera destroyers (e.g., monkeys) a particular concern for camera traps in lowland areas?
  • Does wet vs. dry season impact results at all?
  • Is there a general recommended duration, area, or/and number of camera traps for small-scale community-level surveys?

And if anyone has recommended articles to look into this further, feel free to send them my way!




Hello there. For the beginning, this is quite well written guide: 

https://www.wwf.org.uk/sites/default/files/2019-04/CameraTraps-WWF-guidelines.pdf



As for difference between wet/dry seasons, mostly depends on wind and vegetation growth. In windy periods false triggers (photos of moving leaves, etc.) are much frequent, and even small sticks/grass/leaves can trigger camera trap. Non-stop rain might also cause false triggers (I don't have that experience)

Vegetation growth might limit camera efficiency, leaves and new branches cover your field of view when vegetation grows faster so camera sees less and triggers less. For tropics, it will be all the time I guess :). And if you have both, overgrown vegetation and wind, than it's all false triggers... 



Solution is to clear the area regularly, and to be aware if there is wind or not. You can assess how efficient your camera-trap is depending on the amount of false triggers. 



As for monkeys, I don't know...better to tie cameras using locks and straps, but I would be more concerned about vandalism from humans, than from animals. In our survey area, we have bears, but had only one bitten camera out of  28. Anyway, try not to leave food scents on the camera.



As for how long, and how many cameras...Totally depends on what is your goal.  For a species check-list, or to detect common species, maybe 10 cameras for 2-3 months (if you ensure that all of them work correctly). But you might miss some rare species, or species that migrate and are not there on that season... And it's important not to leave cameras unchecked for too long. (In our case after 2-3 weeks something would always go wrong)…



P.S 

Our camera-trapping survey was conducted in Caucasian mountains, (mainly sub-tropic forests and alpine grasslands), we have bears no monkeys, and we have 4 seasons, so sites differ significantly and so will challenges and solutions...Good luck with the project.  

Hi @laydent ,

I am just an occasional and non-professional user of a camera trap in Costa Rica. I have not experienced destruction of the camera trap by animals, so far. The trap never caught a monkey, but it did catch raccoons, an ocelot, pizotes and olingos. They all left the camera trap alone.

Rain would impact animal behavior obviously and possibly result in false positive triggering of the camera due to moving leaves and/or the rain itself. On the latter, one might try different sensitivity settings to see how your particular camera responds.

Camera traps are supposedly water tight ( and mine has been ), but in the long run seals may erode ( direct exposure to the sun may speed that up ). Also, I am wondering if water tight means rain-water tight, leaving the possibility of air humidity coming into the trap and cause corrosion.

Sorry, but I can not recommend anything to your third point.

I would agree that primates probably aren't your biggest concern, animal-destroyer wise. At least in the Malagasy rainforests, lemurs are highly arboreal so if you have trail cams down low, the lemurs won't come down that far. Neotropical primates are probably similar in that respect (at least compared to African/Asian primates such as baboons & macaques which are more terrestrial). The bigger issue than animals messing up cameras has been people stealing or interfering with them, so trying to put hem off-trail/hidden, locked onto large trees has been important. 

I second the Kays et al paper that @Rolandisimo mentioned above as a great reference & starting point! There is also this paper on camera trap study design, this one on camera trap placement bias and this one on strategic camera trap placement for evaluating different metrics. 

In terms of wet vs dry season, you'll want to make sure that water doesn't accumulate where you're putting up the cameras such that they would potentially become submerged in a flash flood or river-rising/overflowing situation, but you probably already know that :).  

There have been many papers that have looked at the effect of seasonality with camera trap data, but the majority of them are with regard to the actual species activity pattern differences across seasons rather than the effect of season on detection distance. You should consider what your species of interest's activity patterns are in different seasons and how this may impact detection probability. It may also be important in terms of strategically planning your sampling scheme. For example, the mouse & dwarf lemurs in Madagascar hibernate during the cold/dry season so it's not useful to sample for them during those months.