How to Protect Cavity Nests, Tree-mounted Nest Boxes and Feeders - Effective Predator Defense Taking drastic measures to keep the nest safe?

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Protect Cavity Nests, Nest Boxes and Feeders – Effective Predator Defense

Undoubtedly, you are reading this because you want to protect the birds around you.

Now that you are here, this bird nest protection project shows what methods I used to create a predator defense system, built to keep a nest that Northern Flickers made in our apple tree safe from harm.

Of course, this same treatment should also work for other cavity dwellers and for tree-mounted feeders of most types. So far, no creatures (that do not fly) have been able to get to the nest.

Also, check out the video on Creating a Cone Baffle just below the Cavity Nest Video.

See how we built a simple, inexpensive nest box for woodpeckers since this one was becoming too small for so many babies!

Predator protection system - defend cavity nesters, tree-mounted feeders

Easy way to create a Cone Baffle

The problem:

When a pair of Northern Flickers found our apple tree, they decided to make it into their perfect home. They spent weeks hammering, drilling and excavating to make a cavity nest to raise a brood in. 

While we were excited to see them moving in to the neighborhood, we were pretty concerned that the nest was vulnerable. Normally, they choose to make their nests higher off the ground. Since this one was only about six feet up, it would be easily reached by most predators.

We have lots of raccoons and cats that would think of the nest as a cafeteria, and squirrels that would love to move into such spacious digs. With this in mind, we had to act fast!

Version 1 of nest protection - bird spikes everywhere
Version 1.0
Version 2 of nest protection - metal clad
Version 2.0

Version 1.0: The first attempt worked pretty well, or so we thought. Bird B Gone bird spikes were a great idea! I lined both sides of the tree trunk on either side of the nest, and then put two rings of both above the nest, and two below. With so many spikes, it seemed to be a great solution, and it was… for cats anyway.

Then, we put up a security camera to watch the nest. We soon began to notice squirrels were getting past the spikes. Certainly, a very scary moment was when a raccoon managed to somehow get around them and was caught on camera reaching into the nest, attempting to grab the female Flicker who slept in the nest at night. Afterwards, she didn’t sleep in the nest again for weeks after that.

Surprisingly, the issue turned out to be how the bird spikes were mounted. Firstly, I had them cinched down with long zip ties, but those had enough flexibility that the raccoon’s weight allowed them to bend, thus not being spiky at all! Secondly, the other problem was that the squirrels were light enough to just stretch over the spikes.

The solution:

Since the bird spikes were not preventing access or even deterring the marauders, I had to up my defense! I decided that if they couldn’t hold on to anything, they wouldn’t be able to stay on the tree long enough to cause problems. With two apple trees and a fence all near the nest, keeping these bandits out of the trees was unrealistic, and I actually like the squirrels—just not in the nest.

Armor is the solution I came up with. I used sheet aluminum (roll flashing from the hardware store) and surrounded the sides and back of the nest for several feet above and below. Then, to prevent creatures from jumping from the ground onto the uncovered front area around the cavity, I made a cone baffle (see second video above)

Then, I put the bird spikes back up and doubled the amount in an offset, overlapping pattern. This time I only placed them above the nest, and I used screws rather than zip ties. 

The metal was very shiny and I don’t think the Flickers would have been too enamored with all that bling, so I painted it with two satin-finish colors in a sort of camo pattern. All in all, it seems to blend in well, and the Flickers didn’t give it a second thought. 

I must admit, the sheet metal doesn’t look as intimidating as all the spikes did, but this time around, it has been very effective. We, and the Flickers are pleased to announce that five babies were born and raised in the nest last year! And currently, they are prepping the nest for another brood this year too!

The videos above contains more detail about the design of the protection system, and fabricating the metal cladding and the cone baffle.


Summary of Steps:

  1. Make a sheet metal cone baffle using free software linked below
  2. Attach it and sheet metal cladding to the tree
  3. Spray paint the metal in a camouflage pattern
  4. Add bird spikes
  5. Add a wireless security camera 
  6. Watch your bird parents bring up a family!

If you have any tips or tricks, especially for excluding Starlings, please make sure to leave a comment below.

Disclosure: Some of the links below are affiliate links. At no extra cost to you, I may earn a small commission on items bought using them. These are the same recommendations I would make regardless of any compensation. For products that I have older versions of, I recommend the items that I would replace them with if I were buying them new. 

Resources for Protecting Cavity Nests, Tree-Mounted Feeders

Cone Calc for Windows, OSX, Linux

Free Version 
Greatly simplifies the math involved in creating a cone baffle

Cone Calc 3D for Windows, OSX, Linux

Paid Version
Adds full-size printouts, 3D visualization, multiple segments. Full function trial may be all you need.

9-3/4 in. MetalMaster Compound Action Straight Cut Snips

From Amazon
For cutting sheet metal for sheathing and cone baffle. PLEASE wear gloves to protect you from sharp edges!


There are more DIY projects in the works, so stay tuned to Uncharted DIY. Feel free to comment, post photos of your Cavity Nest Predator Protection System or ask questions about this project.

Uncharted DIY is for DIY enthusiasts tackling uncommon projects, utilizing common tools and often on a limited budget

Uncharted DIY is for DIY enthusiasts tackling uncommon projects, utilizing common tools and often on a limited budget