A really difficult thing we encounter as bluebird hosts is after discovering a pair of bluebirds building a nest, and even finding eggs in the nest, suddenly the eggs or nestlings are missing!
The first question that crosses our mind is what happened? Did someone take them? Did something take them. And then we learn the likely cause was a snake, more specifically, a rate snake that invaded the nest and ate the eggs, nestlings and possibly the mother bird.
The best way to prevent snakes from eating what’s inside your bluebird nest box is to mount your it to a metal pole with a tall stovepipe baffle that is at least 8 inches wide and 60 inches tall, though 24-inch baffles help and are readily available.
When it comes to protecting your nesting bluebirds from rat snakes, which is our goal as backyard wildlife stewards, we cannot set our birds up for failure by mounting nest boxes up on wooden posts, fences and trees.
Improperly mounted boxes make it extremely easy for predators to access the nest box and eat everything inside.
And while, to some degree, we do want nature to take its course (though, not in the case of invasive species). Our interference must be educated so that we give all wildlife we manage in our backyard the best chance of survival.
This is where the stovepipe baffle comes into play. It is one of the best methods used to prevent snakes from eating bluebirds, nestlings and eggs.
A stovepipe baffle is a tall cylindrical device that mounts to a nest box pole. It can vary in height and diameter, but it helps destabilize climbing predators and creates a bigger obstacle to minimize their entry into a nest box.
We want to stress that no method of predator protection is 100% perfect. However, there are certain devices that work better than others.
A stovepipe baffle is one of these devices that have been tested for several years across many different bluebird trails, and is found to be a very trustworthy mode of protection from snakes and other climbing predators.
How to make the baffle most effective against snakes
For the baffle to work well, it needs to be at least 8 inches in diameter and 60 inches tall for maximum protection.
24 -inch baffles have been used, and have also been widely recommended in most cases. They are commercially available, which makes them a lot more accessible, especially for newer bluebird landlords.
The downside of this baffle is that it will not protect your nesting bluebirds, tree swallows and chickadees from longer snakes. It’s range of protection is snakes 3 feet in length or shorter.
| Pictured is a juvenile black rat snake. This little guy is a striking silver and black color. It is less than 2 feet tall and is among a rose bush. Notice that the thorns are not a problem.
This is great protection from juvenile and smaller rat snakes, but rat snakes can get as big as 5-7 feet in length.
A 60-inch baffle gives so much better protection. It offers the same protection as the 24-inch baffle, but then also protects from longer snakes.
There are a few downsides to this baffle:
- Your nest box has to be mounted at least 6 feet from the ground so that there is still 1 foot of exposed pole available – 6 inches between the baffle and nest box, and 6 inches from the baffle to the ground so that the baffle can wobble.
- Mounting the pole that high means many people will need a stepladder to monitor and maintain the nest boxes.
- These baffles are not commercially available and would need made.
Making a 8-inch x 60-inch Stovepipe Baffle
There are different approaches to making a stovepipe baffle. One of the easiest ways involves hardware cloth, duct-pipe and a few other supplies.
The instructions available online are not very step-by-step. Instead, they give a labeled diagram that somewhat helps visually explains how to make one.
It is really important when making one with duct pipe (found cheap at many hardware stores), that you are very careful not to cut yourself on the sharp metal.
Another approach to making a taller baffle is using a tall and wide bollard guards. You can find these on Amazon*
To make this type of baffle, you will need a hole-saw to cut an opening that will allow you to put the baffle over the pole and hanger iron strips to mount the baffle.
Bollard guards are only 7 inches in diameter, but some trail monitors are recommending them as an easier-to-make alternative for a DIY stovepipe baffle.
What Other Predator Guards Protect Against Snakes?
There really aren’t any other predator guard that will effectively prevent snakes from entering your bluebird nest boxes except for a Kreuger Trap, and this is not a humane method for bluebirds, tree swallows and most other native cavity nesting birds.
A Kreuger trap is a mesh netting device that goes under the nest box and would snare a snake or possibly other climbing predators.
The problem with this trap is that it is very hard to get snakes out of, and you have to be monitoring allllllllll the time to be able to release snakes quickly.
This type of protection is mostly used for purple martins, and its use is hotly debated in birding communities.
We do not recommend or suggest this method to prevent snakes. Instead, stick with a stovepipe baffle. This is your best way to protect your nesting birds from snakes.
How Do I Protect Fledged Bluebirds From Snakes?
Protecting fledged birds and bluebirds from snakes is very difficult. Snakes will eat birds, especially ones that can’t fly or can’t fly well. A good way to protect is providing bushes and shrubs to allow baby birds to hop into to hide and protect them.
Unfortunately, if you have snakes in your yard, your fledged birds and open nesting birds are incredibly vulnerable to snake predation.
Aside from providing a lot of cover with nearby bushes and shrubs, another way to protect your young birds is not to feed your birds that much during the nesting season.
By increasing the amount of prey in your yard, you will likely increase the amount of predators in your yard. This is seen a lot with hawks starting to frequent yards with big feeding stations.
There is little obligation to feed birds during the nesting season because bugs, which is their primary diet, are plentiful.
Times when bird-feeding is critical is during the winter when bugs are scarce and food competition is high. The other time is during very hot weather when birds must exhaust their energy reserves to forage for food both for themselves and their nestlings.
When it comes to bluebirds, it is important to avoid dried mealworms during the nesting season, and instead provide live mealworms if you’re going to feed birds.
What To Do If I Find a Snake in My Bluebird Nest Box?
Rat snakes are the most common snake that invades bluebird nest boxes (any cavity bird nest box). Fortunately, black rat snakes are not poisonous.
Disclaimer: NEVER ASSUME THE SNAKE IN YOUR NEST BOX IS NOT POISONOUS ON THE CHANCE YOU COULD BE MISIDENTIFYING IT.
If you find a snake in your bluebird nest box, you can try to remove it carefully with a gloved hand AS LONG AS YOU ARE CERTAIN OF THE TYPE OF SNAKE IT IS AND THAT IT IS NOT POISONOUS. Only do this if there are still live birds or eggs in the box. If there are not birds or eggs in the box, leave the box open and exposed to light. The snake should leave on its own. Do not harm it.
We cannot emphasize enough how important it is not to harm native snakes. They play an important role in balancing their ecosystem. And their presence also indirectly helps reduce the flea and tick populations because snakes eat a lot of rodents.
It can be really hard to override our emotions and not lash out at a snake that just ate everything in the nest box, but as backyard stewards that are trying to conserve native wildlife, we must accept this, especially if we did all we could to prevent invasion.
Do Other Types of Snakes Enter Bluebird Boxes?
Rat snakes are the most commonly reported snakes that enter bluebird nest boxes. Bluebird monitors have to worry very little over any other snake, including garter snakes. However, coachwhips have occasionally been reported to enter nest boxes.
There is a lot of animosity when it comes to snakes, and while managing nesting bluebirds, you might have a lot of fear of all types of species. Fortunately most species of snakes are not a threat to bluebird nest boxes.
We do however, want to remind you that many species of snakes may eat birds in the wild, outside of the nest box. This part is out of our control and is up to nature.
A Note on Safety
While rat snakes are not venomous snakes, there are a few safety tips we want to put out there:
- While rat snakes are not poisonous, they still have teeth! Wear thick gloves when monitoring nest boxes.
- Always be aware of your surroundings when monitoring nest boxes. Again, not all snakes are poisonous, but many may bite if they feel threatened. Tap gently on a box, listen out, and slowly open boxes any time you are monitoring them.
- Snakes are not your only worry when monitoring nest boxes – wasps, ants, mice and other wildlife can be on the ground, in the nest box or even hiding in the baffle.
- Though rat snakes are not poisonous, snakes might be misidentified. DO NOT HANDLE A SNAKE AND ASSUME IT IS NOT POISONOUS BECAUSE YOU FOUND IT IN YOUR NEST BOX.
*Links are affiliate links. We get a very small advertising commission if you order a product from an affiliate site. You are not charged extra. Our recommendations on products are deeply researched or come from experience. We do not knowingly recommend products that might endanger our native songbirds.
