– written by Dick Purvis
I have invented a new nestbox which is raccoon resistant. Essentially it is a Tree Branch nestbox with the ends folded up so that it is not so long and awkward to mount. It consists of a box 13″ long, 7 1/2″ wide, and 7 1/2″ high. There is a 1 9/16″ entrance at each end – one near the front and the other near the back. There are 4 1/8″ baffles inside the box spaced 2″ in front of each entry hole. The baffle at one end of the box is against the front of the box and the baffle at the other end of the box is against the back of the box. There are appropriate drainage and ventilation holes.
In order to use the box, a bird enters the entry hole and goes around the baffle to the center of the box to build a nest. They will not build a nest at the entry because there is much too little space. A raccoon is not able to reach the nest because of the baffle. In fact, a raccoon can’t reach any part of the nest to pull it. The second entry hole is an escape hole in case bluebirds are attacked by sparrows (or any other predator). I have tested it last year and a bluebird nested in it successfully. I suspect that bluebirds would prefer most any other nestbox instead of this one because of the restricted entry. We know that in preference tests bluebirds choose the largest, easiest entry, but we can’t let a birdbrain design our nestboxes (Jack Finch).
Preference tests in my area are meaningless. There are no other choices and bluebirds must use whatever I put out. I have tried many designs and they use them all. I would have nearly 100% usage if I didn’t keep expanding into new areas.
Disadvantages of this box is that it takes more material than a conventional box and it is bigger and more difficult to mount. However, if it truly does stop raccoons it would be a great solution for locations with a serious raccoon problem.
The inside nesting area is 6″ by 6″. The entrances are at the small ends – one is at the front edge and the other at the back edge. The birds do not go over or under the baffle but must go around it. Either a front or top opening can be employed. I use a front opening with a 1/4″ ventilation gap at top. A top with large overhangs would be a bit more difficult to open. The dimensions allow the use of standard 8 inch material (7 1/2″ finished).
Unfortunately it does not lend itself well to use as a hanging box which is my specialty. I did hang mine but it was awkward.
MORE INFORMATION & RESOURCES:
More Information and References:
On this website (Sialis.org)
- Bluebirding Basics including minimum requirements for a nestbox
- Monitoring
- House Sparrow Management, including discussion of nestbox style preference
- Nestbox Plans (links)
- Neglected Nestboxes
- The Wrong Nestbox
- Nestbox Material
- Nestbox Mounting Styles – Pros & Cons
- Nestbox Opening Styles – Pros & Cons
- Compare nestboxes (game for children)
- Heat control experiment
- Pressure-treated lumber
Other wonderful resources:
- Nestbox Builder – Fred Stille’s site with plans for many wood and PVC boxes that appeal to bluebirds
Posted with permission from Dick Purvis on (and retrieved from) http://audubon-omaha.org/bbbox/nestbox/baffle.htm
