Wildlife Unit Study Examines Deer Response to Camera Flash
Over the last several years I have written a couple of articles about the use of infrared-triggered cameras to survey deer populations. This is an ongoing project, but I thought our preliminary data addressing some of the assumptions about infrared-triggered camera surveys would be of interest. I will make this a "two-parter," finishing with the next installment in a later month.
One assumption being evaluated has to do with deer response to camera flash. This is significant because the bulk of camera site visitations by deer (at least on the Noble Research Institute Wildlife Unit) occur during nighttime hours. The infrared-triggered camera survey technique assumes that deer response to the flash is minimal or at least that deer use of a camera station is minimally affected by the presence of the camera and flash.
To evaluate this, and to document the reactions of deer to the flash, we used infrared-triggered video cameras. The video camera setups are relatively non-intrusive. They do not emit visible light or audible sounds, and their presence had little or no observable effect on deer behavior. We began monitoring five of our 20 camera locations with the video cameras five days prior to starting the still camera survey. After the five-day "video only" survey, we continued video monitoring for the duration of the still camera survey. The remaining 15 camera locations were monitored with still cameras only during the survey.
Video taken in January 2002 documented a wide range of deer reactions to the camera flash. Some deer had an "explosive" reaction appearing extremely startled and not returning to the bait site at least for the duration of that camera night. Other deer completely ignored the flash, not even looking up when their picture was taken. Many examples of deer behaviors falling between those extremes were also documented.
We also compared use of camera stations by individually identifiable deer (i.e., antlered bucks and ear-tagged does) five days prior to and during the still camera surveys. This allowed us to determine if individual deer using a particular camera station before the still camera survey continued to use the camera station after its initiation.
All five camera locations surveyed with video and still cameras had some individual deer that were observed on video during the pre-still camera survey that did not show up during the still camera survey (see Table 1). The number of deer that discontinued use of a site after initiation of the still camera survey varied by site and ranged from two to eight. This indicates that some avoidance of the camera stations might have taken place when still cameras with a flash were used. It is worth pointing out, however, that most of these deer were observed at least one time at one of the other 19 camera sites during the still camera survey.