Monochrome camera with infrared light source
Infrared lighting has revealed nest box activity never before seen. There is no need to modify the nest box to receive more light. The infrared light source does not produce additional heat and is totally invisible to birds. Nest box entrance hole orientation and the position of the sun are less important when supplemental infrared light is used. Color cameras are not sensitive to infrared light and require more visible light than do monochrome cameras. Also, under low light conditions, color cameras produce poor color.
Continuous video vs time lapse and webcam
Special vcr’s used for security cams can record fewer frames than the standard 30 fps of continuous video. This allows recording 24 hour surveillance on a single tape, however, it also causes the jumpy video seen on store security monitors and web cams. And, more importantly, it misses most of the action. Recording the subtle interactions of parents and nestlings requires continuous video. This has proven as important as the infrared lighting and is well worth the trouble of changing the tapes four times a day.
Cable vs other signal transmission methods
Running a cable from the nest box to a tv inside the house has turned out to be the simplest, cheapest and most trouble free method for me. I have tried a 2.4 Ghz radio transmitter for sending the video (and audio, if a microphone is used) and quickly discarded that idea. My transmitter is rated at 300 ft line-of-sight and worked fairly well at 150 ft line-of-sight. I didn’t try it at a further distance and it didn’t work at all inside our house.. However, the transmitter produced quite a bit of heat - much more than the camera. Also, the transmitter case had many ventilation holes to dissipate the heat, requiring a weatherproof housing separate from the nest box. Unlike the sealed camera case, this perforated housing would likely lead to early failure due to high humidity.
Also, a 12vdc power source is still needed to power the camera, microphone, and now, the transmitter, itself. The small battery packs sold for miniature spy cams are generally underpowered for continuous use of the camera alone. It would be possible to use a car battery at the nest box, retrieving and charging it every few days. Solar powered spy cams are available, but, again underpowered for continual use. A larger solar panel and battery system would easily work, but would be much more expensive. I would suggest using radio transmission of the video signal only if there is some obstacle, such as a raging river, between your house and the nest box.
Protecting the camera cables
For short term use for a single nesting at a song bird box, I simply lay the cable on the ground. So far only one cable has been chewed by a rabbit. For longer periods I run the cable through 1" pvc water pipe. This is quite cheap and reusable. If you don’t glue the joints, it can easily be taken apart and reused elsewhere. At the nest box, I secure the pipe to the box, post, or tree and fit two elbows at the end so the opening faces down to prevent rain from entering. If your nest box is in a tree, wire the pvc in place loosely to allow for flexing of the tree in the wind. Pvc should be run all the way up the tree to the nest box to protect the cable from squirrels.
For permanent cable runs, I bury the cable in pvc. You may want to use a larger pvc pipe in permanent installations to facilitate cable replacement or the addition of more cables. At purple martin sites, where many nests are clustered together, multiple cameras may be desirable. The pipe needs to be buried only a couple inches beneath the surface, since there is no safety hazard with the 12vdc. Ideal sites for permanent underground cable are nest boxes for barn owls, kestrels and screech owls, all of which will frequently nest in a yard, given adequate habitat and privacy.
The pvc pipe doesn’t always have to be run on or under the ground. Today (Jan 4, 2004) I placed a screech owl box 20 ft up in a white pine and ran the pvc pipe from 10' up the tree to just under the roof of an unused chicken coop. The pipe is supported at the middle of the horizontal run by an iron pipe. An ice storm broke off all the branches on the north side of this tree, making an opening suitable for a screech owl nest, even though this species usually nests in deciduous trees. The monitor, vcr and camera power supply are located in the nearby building.
Another option, where the nest box is far from the house, is to run an underground 120vac cable to a shelter near the box and place the vcr and other equipment there, rather than in the house. This precludes watching live video, but is more practical in some situations. I have done this at the front yard kestrel tower, placing all the video equipment in an instrument enclosure in the base of the tower.
Videotaping at remote nest sites
12vdc vcr’s are widely available and rather cheap, as are small 12vdc tv’s (mine cost $30). I haven’t tried a dc vcr yet, but the only problem would be the power requirement. Two car batteries could be rotated as needed, one charging while the other is in use. Lugging a car battery to a remote site might be warranted if your subject is a pileated woodpecker or a kingfisher - both on my need to do list, but neither likely to materialize.
The "spy cams"
There are many sources for relatively inexpensive miniature video cameras. In testing a number of these, I have found that all the medium priced cams give very similar video quality, regardless of the seller's claims or specifications. I couldn't tell the difference between most of them on a small monitor. However, the very cheap cams I have tested were all unsatisfactory, again, regardless of the claims. Many failed rather quickly and all caused sparkles or drop outs in the video. They also had very high contrast, an effect that gives the illusion of sharpness, but actually reduces detail in the image.
One interesting and incredibly cheap spy cam I tried last spring came with cable, ir illumination, a power supply, and was claimed to be waterproof. While the camera was totally unsuitable for nest box video, one of the two that I ordered worked well for monitoring the starling traps, while the other one quit working in one week. The camera actually was weatherproof, because it was sealed in plastic. However, this prevented access to the lens to refocus. All of these cameras come focused at infinity and must be refocused for use in a nest box. Because of their great depth of field, they can be used down to several feet, but not less than that. All the cameras I have tested that weren't weatherproof had the same type of micro lenses that could be slightly screwed out to focus more closely, while all of the weatherproof cams could not be focused for nest box use. The interesting thing about this camera outfit is that the cable was simply telephone wire, which carried the 12vdc, ground, and video. Surprisingly, the totally unshielded phone wire worked all right for my trap video. But, the very day I received the two camera outfits from Harbor Freight, someone emailed asking about shielding for cables. It turns out he had purchased this same camera a year before for use in a wood duck box and found that it worked ok until the local fm radio station powered up. Then, the interference made it unusable. He had also bought two of the cameras and one had failed. Small world! Even so, the low price probably makes that camera outfit useful for some purposes and locations, just not for nest box video. But, in general, don't use unshielded phone wire for transmitting video or audio.
All of the 6 LED infrared cameras I have tested have put out about the same amount of infrared light. Some advertised illumination up to 6 ft, others 12 feet. They all produce a usable image only up to about 2 feet. This is good! Stronger illumination should not be used. While the "near infrared" light is not as dangerous as blue light, it is invisible and thus does not cause the iris to contract in humans or birds to limit the amount of light reaching the retina. The LED's I use barely register 1 footcandle when an incident light meter's sensor is placed directly on the LED. There are quite powerful IR sources used for night photography and security systems that should not be used where a bird or other creature might approach within inches of the source and stare into the camera.