Launched in 2013, Audubon North Carolina’s Bird-Friendly Communities initiative is a partnership program involving more than 20 organizations dedicated to creating a more bird-friendly North Carolina. This vision statement guides the goals and projects of the group: “Bird-friendly communities give birds the opportunity to succeed by providing connected habitat dominated by native plants, minimizing threats posed by the built environment, and engaging people of all ages and backgrounds in stewardship of nature.”
Please welcome guest-blogger Dr. Mark Stanback. Dr. Stanback, professor of biology at Davidson College and advisor to Audubon North Carolina’s Bird-Friendly Communities team, has installed more nest boxes for Brown-headed Nuthatches than anyone in the world.
Read on to find Dr. Stanback’s answers to commonly asked questions about putting up nuthatch nest boxes.
Does it matter which way the hole faces?
No, not at all.
Tree vs. pole: what is the difference in nest success?
I suspect that poles would have higher success. In general, trees are easier for predators to climb than slick poles. Also, more creatures instinctively climb trees to access food. We have data showing that 30 percent of tree-mounted boxes with bluebird nests are depredated (predators take the chicks) whereas nearly all pole-mounted boxes with predator guards are successful.
However, because the entrance holes on nuthatch boxes are considerably smaller than those on bluebird boxes, fewer things can easily reach or climb inside. So, an unprotected nuthatch nest is probably somewhat safer than an unprotected bluebird nest. And because nuthatches tend to nest slightly earlier in the spring than bluebirds, they may face fewer predators (e.g., snakes).
What type of predator baffle works best?
It's more about the size of the baffle than the style. Discs, inverted funnels and stovepipes can all be effective IF they are large enough. A pie pan or an inverted soda bottle will stop nearly nothing. Discs need to be at least 30" in diameter to be effective. Stovepipes need to be at least 30" long.
How high off the ground should I mount the nest box?
In general, the higher, the better. Higher boxes are marginally safer, and birds tend to prefer higher boxes. That said, nuthatches often nest in tree stumps. Natural nests are generally within two meters of the ground. So install your box where it will be convenient for you. And if you have a predator guard on your box, height isn’t an issue.
Do nuthatches prefer boxes mounted on pine trees?
Possibly? I don't know for sure. But it would be tricky to determine this because to test it, you'd have to install boxes on both pines and hardwoods in a mixed-forest situation. But given their love of pines, I would go with pines if I had to choose.
When is the proper time to clean out a nuthatch nest?
Unlike bluebirds, that generally take several weeks off between fledging chicks from one nest and laying eggs in their next, nuthatches will often (though not always) lay new eggs within a few days of the fledging of chicks. Consequently, it's a bad idea to clean out a nuthatch nest as soon as the chicks leave. The female might be ready to lay her first egg when you steal the nest. If they decide to renest, they'll appreciate having the old one. And if they don't renest, it doesn't hurt to leave the nest in there.
So when should you clean out the nest? Many people who monitor bluebird boxes clean out the old nest in late winter as part of their "getting ready for spring" ritual. This is a bad idea for nuthatches. Unlike bluebirds, nuthatches begin "nest"-building as early as December. Even if they don't build a proper nest, they bring in soft plant material and use it to insulate their cavity. And many nuthatches have what looks like a real nest by February. So if you were to clean out your nuthatch boxes in late January, you are depriving your birds of a cozy place to sleep and probably convincing them that this box is not a good place to nest.
I generally clean out my nuthatch nests in late summer or early fall. This way all the House Wrens are done, and I can make sure the box is wasp-free, so it will be ready for fall roosting by nuthatches.