Welcome to Infrared Birding

A number of years ago, I wondered whether infrared technology could be useful for birding, e.g., for finding roosting owls. To my dismay, I found that at the time the available technology was too expensive for casual experimentation. But recently a number of smart-phone attachments have entered the market at prices within reach of the hobbyist. So I made the plunge, and thought, why not share my experiences in a blog?

As of February 2015, the products available in the market are:

  1. Seek Thermal, $250-$300, 208x156 resolution (normal and extended range/XR)
  2. FLIR One, $350, 80x60 resolution
  3. Therm-App, $1600, 384x288 resolution (two lenses: 6.8mm and 19mm)
To allay further suspense, let me just give the bad news: of these, only Therm-App (with the default 19mm lens) has the resolution and range to be useful for birding. The Seek Thermal XR is borderline usable for birding (maybe better than nothing); the regular Seek Thermal and the FLIR One simply won't do the trick.

The Therm-App Camera

Therm-App, with a 19mm lens and a resolution of 384x288 pixels, is the only one of the devices I've tested that has found things I wouldn't have otherwise noticed. Here are some things I have found:

A hotspot in a tree stump coming from a cavity in which I could see, with binoculars, a roosting squirrel.
Therm-App image on the left, Seek Thermal image on the right.

A distant squirrel in Renwick Woods shows up as a bright yellow spot in this Therm-App image. This was far enough away that I could not see the squirrel with my naked eye, but was able to confirm it with binoculars.

A raccoon resting high in a pine tree at Ellis Hollow Preserve shows up as a bright spot in this Therm-App image. This side-by-side with a normal photo of the same scene highlights one challenge with IR birding: correlating the IR image with the visible to pinpoint the location of the hotspot can be difficult.

A second resting raccoon at Ellis Hollow. The photograph on the left shows roughly the naked eye view of the scene (the darkened exposure approximating real conditions on that gloomy morning), with the dotted box indicating the field of view of the Therm-App image shown on the right.

FWIW here are closeups of the two raccoons above, taken with my SLR's 400mm lens from the same spots where the IR images were taken.

So, finding squirrels and raccoons is neat and all, but...

What about the Birds?

Well, I haven't yet found my roosting owl or anything special I wouldn't have seen otherwise. But I do have some datapoints promising the possibility. This is the tree at the Slaterville Springs Dandymart:

From the thermal image you can see that, yes, the Eastern Screech Owl known to roost in that tree was present that day:

And I have found a couple of roosting birds, albeit common ones, that were otherwise hidden and silent. While walking through a grove of hemlocks at Park Preserve I noticed this hotspot:

After fumbling about with my snowshoes in the knee-deep snow, I finally found a vantage from which I could identify the subject as a roosting Blue Jay:

And near the Upper Dam of Six-Mile Creek I saw this hotspot:

The yellow frame shows the Therm-App view.
which turned out to be an American Goldfinch just chillin', moments before the arrival of a frigid snow squall:

Meanwhile, here are a sampling of images to perhaps give a sense of what IR birding sees.

I'd noticed a small bird fly into a tangle of bushes, but didn't see where exactly it had landed. The Therm-App showed its location right away, as the bright spot in the middle. On this winter day (40F/5C) the sun was out and had warmed the exposed tree trunks to a point where the bird did not stand out as much as I'd seen on other occasions. For those wondering, the bird was a sparrow, probably American Tree Sparrow (I was fumbling with the Therm-App and didn't actually get my binoculars on the bird before it flew off :-).

In this tangle of small trees two downy woodpeckers show up clearly in this Therm-App image. The birds were about 50 feet (15m) away and not really visible to the naked eye (except when they moved).

The finches (mostly House Finches) hanging out at Sapsucker Woods look like Christmas lights when seen via a thermal image.

Here's a blue jay that had just flown into a tree, at a distance where it is visible but perhaps not recognizable with the naked eye. This was the same sunny winter day as the sparrow above, so the blue jay does not appear hotter than the tree trunk and does not stand out in the "vivid" color palette (left) that I've come to favor. The bird is more obvious in the grayscale palette (right), but only if you're inspecting regions of the image locally (which can be tiresome in the field). Whatever the case, it makes for a pretty picture.

Looking Ahead

As we enter 2015, I'd like to field test my Therm-App in a number of birding (and other wildlife observation) scenarios, including perhaps:
  • Finding a snowy owl in a field of white (and tinkering with car mounting options, since IR does not penetrate glass windows);
  • Prowling the woods at night;
  • Seeing a woodcock sky dance;
  • Seeing flyover passerines during night migration (I had an opportunity to see this once with a $60,000 camera);
  • Seeing how warmer ambient temperatures will affect the efficacy of infrared birding; etc.

I shall try to update this blog with experiences, discoveries, and tips I hope others will find useful (warning: I can be lazy about such tasks). Meanwhile, if you have an infrared camera and share an interest in birding or wildlife observation in general, I'd love to hear from you (comment below, or email suan.yong at gmail.com). If there is enough interest, we could start a discussion forum, or I could open up this blog to other interested contributors.

Finally, I close with this nifty video of a downy woodpecker exiting a cavity at Stewart Park:


  1. Suan, I am impressed with your use of technology. I use night vision equipment and a flir system to locate owls along the river behind our home. The flir will allow one to focus on an occupied woodpecker hole and binoculars during the day and the night vision equipment at night will allow seeing these fascinating birds. The units I am using cost several thousand dollars. I am hopeful the cost of this technology will go down as these are very useful in wildlife studies.

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  3. Awesome!! Just read your article. I impressed with your lots of informative content about infrared birding.

  4. Have you tried any night vision binoculars/products, as opposed to thermal imaging? I am wondering which would be better for birding.

  5. I've not tried night vision binoculars, but I expect it to be like using binoculars with a flashlight, except the light is invisible and won't spook the subject. If you can find something, it'll be magnified and you'll be able to see details. But if it's camouflaged, it won't be any easier to find than the same camouflaged subject hiding in daylight.

    With thermal, the camo won't work, the bird is literally glowing. But given that most thermal imagers won't be highly magnified (thermal lenses are very expensive), you likely won't see detail. In fact, when I go out at night, a lot of things I see go unidentified: that glowing blob there in the woods: is it a mouse or a bird? and if it's a bird, what kind?