Attracting bluebirds to your backyard is a rewarding experience that offers a glimpse into the life cycle of one of North America’s most beloved songbirds. Among the various birdhouse designs available, the Gilbertson PVC nest box has earned a reputation for being exceptionally effective. This design focuses on the specific needs of bluebirds while addressing common challenges like predator safety and invasive species.
If you are looking to provide a safe haven for bluebirds, understanding the unique benefits of the Gilbertson design is the first step. This guide covers everything from the materials you will need to the specific dimensions required to ensure your local bluebird population thrives.
Why Choose a PVC Nest Box Design?
Traditional wooden birdhouses have been the standard for decades, but PVC designs offer several modern advantages. The Gilbertson style, characterized by its cylindrical shape and white exterior, provides a unique environment that many bluebirds find attractive.
Superior Temperature Control
One of the primary benefits of using white PVC is heat reflection. During the height of the summer nesting season, wooden boxes can become dangerously hot for hatchlings. The white surface of a PVC pipe reflects sunlight, keeping the interior significantly cooler and increasing the survival rate of the brood.
Resistance to Invasive Species
House sparrows are a significant threat to bluebirds, often competing for nesting sites. The Gilbertson design is intentionally shallow. While bluebirds are comfortable in a shallower nesting cavity, house sparrows often prefer deeper spaces, making this design a natural deterrent against these aggressive competitors.
Durability and Maintenance
Unlike wood, PVC does not rot, warp, or crack when exposed to the elements. These boxes can last for many years with minimal upkeep. Additionally, the smooth surface of the PVC makes it much harder for climbing predators like raccoons or snakes to gain a foothold.
Essential Materials for Your Nest Box
Building your own nest box is a straightforward project that requires only a few common materials and tools. Most of these items can be found at any local hardware or home improvement store.
- PVC Pipe: You will need a length of 4-inch diameter thin-wall PVC pipe (often labeled as SDR 35 or drainage pipe).
- Wood for the Roof: A piece of cedar or redwood roughly 1 inch thick. These woods are naturally weather-resistant.
- Wood for the Floor: A small circular piece of wood that fits snugly inside the bottom of the PVC pipe.
- Fasteners: Stainless steel or galvanized screws to prevent rusting.
- Mounting Pole: A 1/2-inch or 3/4-inch electrical conduit (EMT) is the standard choice for mounting.
Step-by-Step Construction Guide
Creating the box involves a few precise cuts. Precision is important because bluebirds are picky about the size of their entrance holes and the security of their nesting cavity.
1. Cutting the PVC Body
Cut the 4-inch PVC pipe into a section approximately 7 inches long. This creates a compact, efficient nesting space. Ensure the cuts are straight so the roof and floor sit flush against the pipe.
2. Creating the Entrance Hole
The entrance hole is the most critical measurement. For Eastern Bluebirds, the hole should be exactly 1.5 inches in diameter. If you are in an area with Western or Mountain Bluebirds, you may need to increase this to 1 9/16 inches. Use a hole saw bit for a clean, professional finish.
3. Preparing the Roof and Floor
Cut your roof wood into a square or rectangle that extends at least 2 inches beyond the pipe on all sides to provide shade and rain protection. The floor should be a wooden disc with small notches cut out of the edges to allow for drainage. Secure the floor at the bottom of the pipe using a few small screws.
4. Ventilation and Drainage
Birds need fresh air and a dry environment. Drill several small holes (about 1/4 inch) near the top of the PVC pipe just under the roofline for ventilation. Ensure the floor has drainage gaps so that any rain that blows in can easily escape.
Optimal Dimensions for Success
Following specific dimensions ensures the box is safe and functional. Deviation from these standards can result in a box that is either unused or dangerous for the birds.
- Interior Diameter: 4 inches (standard PVC pipe size).
- Entrance Hole Height: 1.5 inches from the top of the pipe.
- Cavity Depth: Roughly 4.5 to 5 inches from the bottom of the entrance hole to the floor.
- Roof Overhang: 2 to 3 inches to protect against predators and weather.
How to Install Your Nest Box
Location is just as important as the design of the box itself. Bluebirds prefer open spaces with low grass where they can easily hunt for insects.
Choosing the Right Location
Place your nest box in an open area like a large backyard, field, or park. Avoid areas with dense brush or deep woods, as these are more likely to attract wrens or chickadees rather than bluebirds. Facing the entrance toward a nearby tree or fence (about 10-20 feet away) gives fledglings a safe place to land during their first flight.
Mounting the Box
Mount the box on a metal pole rather than a tree or fence post. Trees and fences provide easy access for cats, raccoons, and squirrels. Using a smooth metal conduit makes it much harder for predators to climb. The box should be situated about 4 to 6 feet off the ground for easy monitoring and maintenance.
Maintenance and Seasonal Care
To keep your bluebird trail healthy, you must perform regular maintenance. A neglected box can become a breeding ground for parasites or may be taken over by unwanted species.
Cleaning After Each Brood
Bluebirds often raise two or even three broods in a single season. Once the fledglings have left the nest, remove the old nesting material and wipe the interior with a weak bleach solution (one part bleach to ten parts water). This encourages the parents to return for a second nesting and prevents the buildup of mites.
Winter Preparation
In the late fall, give the box one final cleaning. Some birders choose to leave the boxes up during winter to provide a roosting spot for birds during cold nights. Others prefer to take them down and store them in a garage to extend the life of the wooden components.
Conclusion
The Gilbertson PVC nest box is a highly effective tool for anyone interested in bird conservation. By following these plans and installation tips, you create a safe, temperature-controlled environment that specifically caters to the needs of bluebirds. This simple weekend project can lead to years of enjoyment as you watch generations of bluebirds flourish in your own backyard. For more information on local bird species or advanced gardening tips to attract wildlife, explore our other guides on habitat conservation and outdoor projects.