Frank wrote this up and asked me to post it.
Recently, we’ve received several messages, and another blogger has mentioned the use of game cameras – also referred to as trail cams, or camera traps – as aids in searching for Ivory-billed Woodpeckers. We’ve been deploying trail cams since early 2009, and have had some intriguing “hits”. They have been useful in many ways, and we have learned a lot about the feeding habits of other woodpeckers – specifically, Pileated, Hairy, and Red-bellied – that were useful in giving Mark insights into the type of feeding sign that we have come to believe is most likely diagnostic for ivorybills. In dozens of deployments, and hundreds of hours of searching with boots on the ground, and sometimes in the water, we have NEVER observed a woodpecker performing the type of scaling that we have come to suspect is diagnostic.
While trail cams are a valuable tool in our arsenal, they are, by no means infallible. There are many pitfalls involved in their use. Firstly, they are not designed to capture birds – in fact many common species of birds are almost unidentifiable in the images. Birds do not set off the motion triggers that these cameras use, and why should they? The cameras are designed for use along trails and adjacent to food plots used by larger mammals – usually whitetail deer. I have tested the Reconyx “Hyperfire” cameras that we use, and even a large Wild Turkey at fairly close range will not trigger one, even at its most sensitive setting, while a relatively small (terrier size) dog will trigger one from a distance of twenty-five or more yards. The manufacturer has indicated to me that there is “something about the way birds reflect light in the visible and infrared spectrum” that makes the cameras’ triggering units unable to “see” them.
As a result, ivorybill hunters must find a camera that will operate in time lapse mode. For all their disadvantages (3.1 megapixels, low resolution among them) the Reconyx cameras offer the best time lapse mode available at an affordable price. This, in and of itself, though, becomes a handicap, as the card for each camera must be programmed, using a proprietary program provided by Reconyx, on a PC. One programs the card, inserts it into the camera, and hopes for the best – there is no way to check and see if the card/camera combination is functioning properly. This has led to many wasted deployments. Additionally, there is the problem of how often should the camera take a photo vs. storage capacity of the card. The cams are designed for 8 gig cards, sometimes they will function with a 16 gig card, but will universally malfunction with a 32 gig card. 8 gigs is usually enough for a ten-day deployment with the camera time constrained to take a photo every twenty seconds for ten hours a day – you do get to select the hours of operation though. While every twenty seconds would seem to be quite often (and a full 8 gig card will store upwards of thirty thousand images), perform a little test for yourself. Go out to your favorite birdwatching location and see how long a bird – any arboreal non-raptor species – stays in one location for twenty or more seconds. Captures of birds on game cams are a relatively rare event – I have looked at nearly a million Reconyx photographs and have picked up birds of any kind in perhaps a thousand images – identifiable birds in maybe two hundred.
The very first thing that has to be done when using game cams is to select a location where you suspect an ivorybill is likely to show up. This could be a tree with scaled bark and other indications that an ivorybill has visited it, or a cavity with features that seem to match photographs of known ivorybill cavities. Both of these are, at best, iffy propositions. One has to find the tree, geotag it (you do have a good GPS unit, right?) then return to the location – often several miles of hiking through some pretty rough and secluded forest, carrying the camera and its mounting system – which weighs around ten pounds. Then the camera and mount have to be positioned to get the target near the center of the frame, which gets easier with practice, and the camera and mount hidden and intervening vegetation trimmed so as not to interfere with the line-of-sight. Once all this has been done the camera can be turned on, armed, and left to do its thing.
Assuming that everything up to this point has been done perfectly, in ten days or so, it’s time to change cards, or retrieve the cam. Now one is faced with the daunting prospect of going through some thirty-thousand photos looking for anything “interesting”. Often, several days of images will pass without a single “hit” of any kind. It’s often a relief to spot even a small woodpecker or squirrel, to remind one that the target is part of a living ecosystem.
The series shown here is exceptional in terms of quantity of images, quality, and our ability to place the camera. (It may be significant for what it doesn’t show, a Pileated doing the type of scaling we think is diagnostic.) Even so, it was not possible to cover the entire target tree.
As I stated earlier, these cameras, within their limitations, are useful tools, but for my money, nothing really beats the good old MK I MOD I human eyeball. But at this point, that’s just not enough …
In addition to the suggestive photos we’ve already posted, we recently obtained some pictures at the site where last week’s double knock was recorded. Because we find some of these pictures intriguing but inconclusive, we have deployed two cameras in hopes that the double placement will yield an identifiable photograph. The first picture, taken under good lighting conditions, clearly shows a Red-headed Woodpecker (there is a roost at the very top of the snag); the others are ambiguous. We are posting them unedited and leave it to you to speculate about what they may be. We recognize that none of these are of anywhere near good enough quality to be identifiable as ivorybills, but we are doing some further analysis to get a clearer sense of scale. The camera placement is 85’ from the tree; the branches behind the tree are an additional 15” away. My preliminary estimate of the diameter of the tree just above the jug handle on the right is approximately 18”.
I have taken careful measurements using a camera with known lens settings and a rangefinder – when the weather is more congenial, I will make comparison shots at the exact measured ranges. This should give a margin of error of ~1″ or less.
4 thoughts on “The Pros and Cons of Trail Cams”
Interesting article. I’ve recently returned from Cuba after using trail cameras to try to find Zapata Rail. I used six Bushnell Trophy Cams set along purpose-cut ‘rides’ in the sawgrass swamp. We got photos of birds – Great Blue Heron, Great Egret, Little Blue Heron, Limpkin, Purple Gallinule – without any problems. We didn’t get any rail photos at all, even though we saw Sora in the rides and apparently within range. We suspected that the camera wasn’t sensitive enough but then obtained photos of Northern Waterthrush and Common Yellowthroat! My conclusion was that the vegetation left in the rides was obscuring the birds from the camera’s sensor. The problem is that if you clear the ride completely, rails don’t like to use, or even cross them. I started out setting the cameras to fire every so many minutes but this meant sifting hundreds of images every day. In the end I set them all to fire two photos, one second apart for each triggering of the sensor. I would recommend the Bushnell – it’s far lighter to carry than ten pounds (500g) and the mounting system is a simple strap to put around any tree – or in our case we just cut branches to a suitable length and stuck them in the swamp. Also the quality of the images is superb.
Thank you Andy! Evidently the technology has evolved quite a bit, when we purchased the cams we’re using – late 2009 – they were the only ones that had time lapse. At what distance would you guess the Yellowthroat triggered the cam? In our current deployment, the distance to the aimpoint on the tree is exactly 28 yards. Also, I’m not too fond of strapping them to a tree. I do like the universal mounting system we’ve been using – it uses a standard camera mount screw that I think all trail cams have built in – it enables us to aim to a specific point near center of frame.
Well, the Yellowthroat was fairly close, I think – maybe only a few yards away. The Bushnell records images (5MP with 3MP compression and 6MP interpolation) and videos (720 x 480p) directly onto an internal SD card. The PIR motion sensor is triggered up to a distance of 13 metres (45 feet) and has adjustable sensitivity (low, medium, high or auto). Images and videos are in full colour during the day, and black and white at night, or in low-light settings. Hyper night vision technology ensures that night-time images are crisp and clear.
The Trophy Cam 2014 has a trigger speed of 0.8 seconds and recovery between triggers is 1 second. The adjustable trigger interval ranges from 1 second to 60 minutes. It is also possible to specify how many images to capture per trigger (1 to 3). The 2x Field Scan function uses time lapse technology to capture images at specified intervals (1 minute to 1 hour) between the hours of your choice. You can programme two separate time lapse windows so that you can monitor both dusk and dawn activity at your survey site.
The Trophy Cam 2014 is powered by 8 AA batteries which will last up to a year. The unit has a standard tripod socket and comes with a web belt for attaching to a tree or post. There is also available (separately) a tree bracket which screws into any tree or fence post whilst the Bushnell Trophy Cam attaches to the mounting thread on the opposite end of the bracket. The adjustable head allows mounting flexibility and an easily adjustable shooting angle.
When it comes time to sort through all the images, have you considered the “mechanical turk” method, which is a kind of crowdsourcing:
or (what astronomers do to find comets and other objects against a standard background) blink interferometry? Perhaps a company would donate this service to your efforts.