Chris' Screech Owl Nest Box for 1999/2000

The eastern screech owl nest box used here is a prototype that provides a nesting cavity of 8" x 8" x 17". The entrance hole is 3" in diameter, and is located 12" above the floor. A 1/4" vent slot runs two inches above the entrance hole. This nest box design provides for removable left and right side modules, a removable roof module, and a fold-down front for easy interior access.

The images presented here were acquired by a monochrome video camera mounted in a camera box installed in the right side module socket. The camera is sensitive to both visible and infrared (IR) light, and its enclosure includes an array of infrared illuminators (partly visible in top corners of the images). A pane of glass separates the occupants of the nest box from the interior of the camera box. Another pane prevents access to the "attic" area and the roof module (dimly visible at the top of the images). The left side module socket is filled with a wall module, the interior surface of which is conventional pegboard (rough side exposed). The one inch spacing between holes in the pegboard provides a convenient means of measuring objects in the box.

As with my previous owl nest boxes, an infrared beam shot across the entry hole allows a computer to detect and log entries to, and exits from, the box. This easily detects the comings and goings of birds, squirrels and other sizeable critters, but it is oblivious to the geckos as they prefer to come and go by way of the 1/4" vent slot above the entry hole.

• Eastern Screech Owl Nest Box Cam, 6-Mar-2000 - The camera in the nest box is now on-line for all to see. Follow the link above.
• Screech Owl and Fox Squirrel, 20-Dec-1999, 6:44 AM CST - I knew these encounters must take place, but this is the first time I've seen one: a screech owl comes to the nest box only to find a fox squirrel sleeping in it. The owl realizes his mistake with his head still in the entryway and departs immediately. Meanwhile the squirrel, awakened by the arrival of the owl, leaps up to investigate.
  • Movie: Owl Meets Squirrel (356K, 0:07 at 2FPS)

  Since the object of this exercise is to provide a nesting cavity for screech owls, rather than our abundant fox squirrels, this encounter is another indication that I will have to intervene on behalf of the owls.

• Screech Owl, 20-Nov-1999, 6:29 AM CST - This is the third exploration of the box by an owl that has been caught on video. As in the past, the unreachable interior of the camera module seems to be the focus of the owl's curiousity. It is the strangest part of the box, so that's understandable. As long as it doesn't actually bother the owls, the box stands a good chance of being selected as a nest site. Also as in the past, the infrared lighting in the lower part of the prototype is poor, and the owl is mostly seen in silhouette.
  • Movie: Exploration 3 (2.4MB, 1:18 at 2FPS)
  • Still: Staring Owl

  There have probably been other explorations since October 1st, but bad wiring resulted in a long period of unreliable entryway sensor data. All wiring was replaced a few weeks ago, and things have been working flawlessly since then. During that period one probable, but unrecorded, visit occurred.

• Fox Squirrels, 30-Oct-1999 - Junior fox squirrel wrestling. Two of the kids at play in the box. I often see them playing like this during the day, so here's an excerpt.
  • Movie: Junior fox squirrel wrestling (4.0MB, 1:04 at 6FPS)
• Owl?, 24-Oct-1999 - The entryway sensor reported that something visited the box around 2:46 AM. Unfortunately, no video recording was occurring at the time. A look at the live picture from the box shortly afterward showed that the squirrels were sleeping soundly (not even doing their usual tossing and turning), so it wasn't one of them in the entryway, nor were they disturbed by whatever did visit. I think this pretty much rules-out climbing predators, and leaves my owl as the best candidate.
• Owl box chassis, 19-Oct-1999 - Views of the chassis of this modular nest box design.
  • Movies: Large (594K), Small (187K)
  • Still: Looking up into the "attick"
• Owl?, 18-Oct-1999 - Entryway logs suggest that my local owl may be avoiding the cold and rain by roosting in my old non-video-equipped nest box. The male owl routinely roosted in that box during this last winter for the same reasons. Construction of the two copies of the final version of the video-equipped box is progressing and, with another month or so of work, they should be ready to replace the prototype box and the remaining non-video-equipped nest box. I'll have eyes everywhere, and owl's will have a choice of nest sites (as will the squirrels).
• Owl and Squirrels, 17-Oct-1999 - The entryway logs indicate that someone spent a few minutes in the entryway about an hour before sunrise. This says "owl" to me, but whoever it was didn't enter the box, so the evening's videotape has nothing to show. Later in the morning, as Austin's weather abruptly turned cold and wet (after 3+ months of drought, the "wet" is welcome), the squirrels returned to the nest box. Looks like Mom and the three kids. The fourth kid hasn't been seen since early in their initial occupation of the box.
• Prototype nest box photographs, 16-Oct-1999 - Have been meaning to add photos of the prototype to this page for a while, but haven't finished-off the role of film they're on. A digital camera provided a workaround.
  • Prototype in tree, on mounting bracket - Note that the mounting bracket includes a pulley. The box is far too large and heavy to be carried up a ladder, as my previous nest boxes were, and the pulley system is a great deal more convenient in any case.
  • Camera module - The module is removed from the box and its glass wall and video camera face the viewer, much as they would face the occupants of the nest box. Note that the camera is mounted on a prototyping PC board which stands-off from the back wall of the box on four 3" long machine screws. By moving the nuts on those screws, the video camera's front-to-back position may be adjusted, as can it's angle, to a limited degree. The blocks of wood positioned at the top of the module hold the infrared LEDs that provide night-time illumination in the box.
  • Camera module socket - The module and the chassis socket into which it fits are shown. Note the two 2" carriage bolts projecting from the chassis above and below the socket. The bolts fit through holes in the exterior of the camera module, and the module is then secured to the bolts with wing nuts.
• Empty, 14-Oct-1999 - Saw a mother fox squirrel and three kids near the birdfeeders. I don't know that they were the same squirrels who occupied the box, but I choose to believe so.
• Empty, 11-Oct-1999 - The family of fox squirrels left the box yesterday morning and hasn't returned. Have caught sight of a pair of squirrels that were probably Mom and one of the youngsters. Don't know what's become of the three other kids.
• Fox Squirrels, 2-Oct-1999 - A family of fox squirrels that seems to have been nesting in the upper branches of the same tree in which the box is mounted have claimed the box. There are four well developed, young squirrels and their mother, who is still nursing them. Two of the four young seem to like to spend the nights elsewhere, but are frequently snoozing in the box during the day.
  • Movies: Sleepless youngster (2.8MB, 2:36 at 2FPS), Mom visit chaos (1.4MB, 0:28 at 6FPS)
  • Stills: Lookin' at ya, Midnight snack, Squirrel on glass, Two in entryway
• E. Screech Owl, 1-Oct-1999, 6:46 AM CDT (IR from videotape) - The owl returns for another look around. He seems to have come mostly to contemplate the camera enclosure; maybe it's the glass, perhaps the camera within it, or just possibly his reflection in the glass is what interests him. After pecking the glass once, he leaves a few seconds later. (Do I know it's a male owl? No, it's just an educated guess.)
  • Movie (2.7MB, 0:52 at 4FPS)
• E. Screech Owl, 30-Sep-1999, 12:33 AM CDT (IR) - Definitely an owl this time; the owl has finally entered the box to explore it properly. Apparently the 3" deep, 3" diameter entry hole is a little bit of a tight squeeze, but if the owl will tolerate the fit, the box will be a safer nest site because of it.
  • Movies: Large (10.5MB, 1:28 at 2FPS), Small (2.1MB, 1:28 at 2FPS)
  • Stills: [1], [2], [3], [4], [5]
• E. Screech Owl (probably), 26-Sep-1999, 6:23 AM CDT (IR) - Like the previous probable visit, the owl didn't emerge from the entryway, but it did come somewhat more into view. It also spent a little longer on this investigation, almost leaving once, then returning for another look around.
  • Still (from videotape)
• E. Screech Owl (probably), 23-Sep-1999 (IR) (still, from videotape) - The computer detected an object in the entryway for a few seconds at 6:09 AM, an hour and ten minutes before sunrise. The videotape unambiguously confirms that something was in the entryway (the computer's entryway sensor doesn't hallucinate in any case), but that something didn't emerge from the entry tunnel. This still image is the most revealing frame found on the videotape. I believe the dim shape in the entryway is the owl's right eye and its surrounding light colored facial feathers. This is the first time a screech owl has entered the box.
• Starling, 15-Sep-1999 (visible) (0.8MB, 0:40 at 2FPS)
• Starling, ??-Sep-1999 (visible) (1.3MB, 1:08 at 2FPS)
• Gecko, 8-Sep-1999 (IR) - [1], [2]
• Gecko, 7-Sep-1999 (IR)
• Starling, 6-Sep-1999 (visible)
  • Movie (1.3MB, 1:54 at 2FPS)
  • Stills: [1] [2] [3] [3]
• Owl box chassis (no front, side, or top modules). Scale in inches.

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