Fence Mounted Nestbox Design

I was wondering if any mad scientist bluebirders have come up with a predator-deterrent mount better than this, to mount boxes on fences where there is no other option (no digging allowed, no trees to hang boxes from.) The concern is protecting the nestbox contents from snakes and climbing mammalian predators. A set up like this would also address the problem of large animals (horses, cows) inside the fence rubbing up against boxes. I’m probably making this too complicated.

Some ideas from folks on the Bluebird_L:

• See Bluebird Monitor’s Guide – attach a socket to an existing fence post and install a nestbox mounted to conduit that you can slide down into the socket and then remove the whole rig to check the nestbox. You can easily get the pole and nestbox to where it is 5 feet above the existing fence and install what ever guards you want on the pole.
• Maybe a hanger from the pole would work?
• Strap a 10-12 foot pole to the fence post attach a right angle bracket at the top and use a Linda Violett-style tree mounting system to attach and retrieve the nest boxes. The long pole would receive plenty of support from the fence.
• Maybe a shepherd’s hook (like those used to attach hanging plants to a deck railing) modified to include an anti-squirrel dome baffle over the roof?
• A dish-shaped baffle would probably be a problem if the wind caught it and moved it (ala an umbrella.) Better to go with the hardware cloth if anything was on the horizontal pole.
• A large roof overhang would also help deter mammalian predators that would sit on top of the box and try and reach in through the entrance hole. A deeper nestbox will also help.

Noel Guards are an option, but some monitors find birds avoid boxes with them pre-installed. It is probably better to put them on after the first egg is laid. They won’t deter snakes.

More Information:

• Is it okay to mount a nestbox on a tree?
• Predator baffle options
• Noel Guards
• Predator ID & Solutions – what happened?
• Boxes by roadsides
• Fred Stille’s fabulous website with nestbox plans
• Mounting options, pros and cons