Plumbing a Bluebird Nest Box Pole of 1/2-Inch Conduit Over Rebar With a Magnetic Post Level: 2 Feet of Rebar Showing, a 5-Foot Pole, and the Box Floor at 5 Feet

Disclosure: This post contains affiliate links. If you purchase through these links, we may earn a small commission at no extra cost to you.

A bluebird box on a leaning pole sits at a tilt, makes predator guards hang crooked, and works looser every windy day. The fix is cheap: a 4-foot length of 1/2-inch rebar driven plumb, a 5-foot piece of 1/2-inch EMT conduit slipped over it, and a magnetic post level riding the steel the whole way down.

How do you keep a bluebird box pole straight and stable?

Drive a 4-foot length of 1/2-inch rebar until about 2 feet remains above ground, checking plumb on two sides as it goes. Slide a 5-foot conduit pole with an EMT coupler over it, tighten the set screws at ground level, then strap the box on top.

Cornell Lab of Ornithology's NestWatch Nest Box Installation Guide uses exactly that kit. It calls for a 4-foot section of 1/2-inch rebar with about 2 feet left above ground, a 5-foot section of 1/2-inch conduit, and a 1/2-inch EMT coupler with set screws. It advises leaving about 6 inches of space between a predator guard and the nest box floor.

The guide also says to check the site for utility lines first, because rebar driven into an electrical cable could injure you. It recommends a rubber mallet so the rebar top doesn't flatten and jam the coupler.

Texas Parks and Wildlife's Bluebirds in Texas handbook puts the base of the box ideally 5 or 6 feet from the ground. It recommends galvanized steel or EMT conduit poles of 3/4 to 1 inch, notes that T-posts and wooden poles are easy for predators to climb, and suggests facing the entrance somewhat east.

Two Pole Setups Compared

Part	NestWatch kit	TPWD option
Anchor	4 ft. of 1/2-in. rebar	4 ft. rebar or 1/2-in. EMT
Pole	5 ft. of 1/2-in. conduit	3/4-1 in. steel or EMT
Joint	EMT coupler, 2 set screws	Pole slid over anchor
Box height	Box on pole top	Floor 5-6 ft. up
Guard	About 6 in. below floor	Baffle on pole

With 2 feet of rebar buried and the coupler at ground level, a 5-foot pole puts the box floor at about 5 feet. That is the low end of the TPWD range and still easy to check from the ground.

Why Plumb Matters Here

The conduit follows the rebar, so any lean you drive into the rebar grows all the way up to the box. A rebar that leans 1 inch over the 2 feet above ground puts the top of the 5-foot pole about 2-1/2 inches off center.

Materials and Tools

• Magnetic post level with vials on two faces that holds to round steel
• One 4-foot length of 1/2-inch rebar and a rubber mallet or small sledge
• One 5-foot length of 1/2-inch EMT conduit and one 1/2-inch EMT set-screw coupler
• An M5 machine screw for the coupler's lower set screw, as the NestWatch guide specifies
• Two 2-hole pipe straps, four 3/4-inch screws, and a screwdriver
• Work gloves and safety glasses

Pole Steps

1. Check for utilities. Call 811 or have lines marked before driving any rebar.
2. Start the rebar. Tap it about 6 inches into the soil, then clamp the magnetic level to it.
3. Drive and watch. Drive with short mallet strokes, checking both vials every few blows and pushing the bar upright while it is still shallow.
4. Stop at 2 feet. Leave about 2 feet of rebar showing.
5. Prep the coupler. Tighten the coupler's upper screw onto the conduit and swap the bottom screw for the M5 machine screw.
6. Slide it on. Lower the conduit coupler-side down over the rebar until the coupler reaches ground level.
7. Check plumb again. Move the level to the conduit, then tighten the bottom screw against the rebar.
8. Add the guard. Fit a predator guard so about 6 inches of space remains below the box floor.
9. Strap the box. Fasten the box to the pole top with both pipe straps, entrance facing roughly east.

Pole and Baffle Safety

• Wear safety glasses while driving rebar, since mallet strikes can chip steel
• Cap or cover the rebar top until the conduit goes on so no one falls onto it
• Don't drive near marked utility lines, even if the marks seem a few feet off
• Keep fingers clear of the coupler when the conduit drops onto the rebar

TPWD's Kingston-style baffle wraps a disk of 1/2-inch hardware cloth inside an 8-inch stovepipe. Cutting that disk cleanly is covered in how to cut hardware cloth without sharp edges, and mesh choices are in the hardware cloth mesh size and gauge guide.

Driving steel straight in hard ground is covered in driving 6-foot and 8-foot T-posts in clay and rocky soil. For chicken nest boxes rather than bird boxes, see how to predator-proof external nesting boxes.

FAQ

Can I mount the box on a fence post instead?

TPWD notes that T-posts, wooden poles, and other traditional supports are easy for many predators to climb. A smooth steel pole with a guard is harder to get past.

Why does the box keep spinning on the pole?

The bottom set screw isn't biting the rebar. Tighten it firmly at ground level, as the NestWatch guide shows.