Tips from an expert on how to build a proper birdhouse
Larry Zoller is attuned to the sounds of birds. During conversation, he’ll pause if he hears one and then identify it.
“Red-shouldered hawk,” he’ll announce, or “red-bellied woodpecker,” before resuming what he was saying. Appropriately, this bird-fascinated man – a retired teacher – is the president of the Wake Audubon Society. Also appropriately, there are bird boxes throughout the yard of his suburban Apex home. Some are designed for bluebirds and nuthatches but one larger one, built for a screech owl, currently houses a different kind of beast.
“I love God’s creatures, but squirrel is not high on my list,” Zoller says with a smile.
Squirrels, after all, are only one animal that can displace birds from these boxes; others, like snakes, cats and invasive birds like starlings, can attack and kill birds if their homes aren’t built or placed properly.
Zoller provided us with handy tips on building sturdy, practical bird boxes. For those who want to go a step further and decorate the boxes, perhaps even for JC Raulston Arboretum’s 17th Annual Birdhouse Competition on March 31-April 1, Zoller’s tips could be used to ensure the birdhouses are not only creative, but useful and safe for their target residents.
For the humans placing birdhouses in their yards, the rewards can be both ethical and aesthetic.
“Make sure it’s away from predators, but make sure it’s where you can see it,” he advises. “That’s where the value is.”
For the love of birds
Having been an avid birder for five decades, Zoller says a bird box is a good entry point to the world he loves.
If you have a bird nesting in your box, he posits, you’ll learn more about it. And if you discover there’s pressure on the species living in your yard, you’ll want to do what you can to help that bird survive. The brown-headed nuthatch, he says, is one species warranting concern. Through research, the National Audubon Society has found that it and other birds will soon be absent statewide because of climate change, Zoller says. Experienced birders keep tabs on this population change through regular counts.
“Their range will move, but a number of them will go extinct – in fact, a surprising number,” he says. “If you were going to go to the Audubon website and check it out, you would find that it’s a shocking percentage of birds that either won’t be in North Carolina or will be gone from the face of the earth.”
As it gets warmer, he explains, birds can’t just move their ranges; the temperature may change, but the ecosystem these creatures are adapted to won’t simply move with it.
“When miners used to go in a cave they’d have a canary, and the bird would die,” Zoller says. “Well, these birds are our canaries.”
Birdhouse-building tips
Here are some of Zoller’s bird box tips.
Qualities and construction: A bird box should have a sturdy back and be made of inch-thick untreated wood (this will end up a little smaller than an inch once planed, Zoller notes). He recesses the base and cuts off its corners so water doesn’t gather inside the house, and ensures the box has vent holes so its residents don’t overheat. Accordingly, inch-thick sides insulate birds against extreme temperatures.
“You want a roof that’s angled and that sticks out,” Zoller says. This keeps water from getting in, but also provides protection from predators.
Door holes are different sizes for different birds: an inch and a half hole, for instance, allows bluebirds in but is narrow enough to keep more aggressive starlings from entering and pecking the bluebirds. Nuthatch boxes need an inch and a quarter holes. Squirrels can chew up door holes to get into bird boxes, so you may need to add a second block or a metal plate with a hole as well.
Inside and below the hole there should be a “ladder” of grooves so nestlings can climb out.
No perch necessary: Birds don’t need perches on their houses. These simply give predators easier access, Zoller says.
Cleaning: Birds are going to use the bathroom in their bird boxes, and these should be cleaned, both for smell and to keep parasites under control. If you pre-drill holes in the side walls and top of the front panel and then attach that panel with galvanized deck screws, you can open the front to clean your bird box. (Wear gloves for cleaning, Zoller recommends, and leave the panel propped open to air out for a few days.)
“A raccoon is smart enough to know how to open it,” Zoller notes, so he drills a hole at an angle and rests a nail in it to lock the panel shut.
Placement and protection: Boxes need to be placed where the birds won’t fry on a hot day or be exposed to predators like cats, raccoons, snakes or other birds. A baffle on the post can keep animals from climbing to the bird box, though pre-made posts like this run at about $60, Zoller says. His budget-friendly homemade solution is a metal fence stake with a baffle made of a 2-inch PVC pipe and cap. A stainless steel bolt centers the pipe.
“We’re not responsible for the birds that are flying around, but we are responsible for the birds we put in a box,” he says. People can also be responsible for birds by keeping their cats indoors, Zoller says.
What birds need: Bird boxes are not just used for nesting, which is a relatively brief time in the bird’s year. “They’re also used for roosting in the winter when it’s cold,” Zoller says. “They’re warm-blooded animals, so they’ll actually pile in together and share the warmth and that’s their roost.” Birds who use bird boxes are species who typically nest in cavities in dead trees; people tend to cut these down, so bird boxes serve a similar function.
Enter the birdhouse competition
JC Raulston Arboretum’s 17th Annual Birdhouse Competition is open to both children and adults. The competition aims to raise awareness about bird habitats.
Adults have three categories: Serious, Flights of Fancy and College Students (themed after the college or major). Serious entries are “working birdhouses” and are judged on craftsmanship, functionality for humans and birds, mountability and aesthetics. Flights of Fancy entries are described as “decorator birdhouses” and are judged on aesthetics, imaginative theme, craftsmanship and functionality.
Children have categories for ages 4-6, 7-9, 10-12 and 13-16. Entries will be judged on aesthetics, imaginative theme or concept, craftsmanship and functionality for birds.
Competitors are not limited to one entry; all entries should be portable. All entries are due at the Raleigh arboretum between 10 a.m.-6 p.m. March 31.
More details on entry requirements can be found at jcra.ncsu.edu/birdhouses.
The public can also view the entries and vote for their favorite birdhouse from 9 a.m.-4 p.m. April 1.
Birding resources
The National Audobon Society has a mission to protect birds and their habitats. Info: audubon.org.
Wake Audubon Society meets at 7:30 p.m. on the second Tuesday of the month at the N.C. Museum of Natural Science. Info: wakeaudubon.org.
Nestwatch, operated by the Cornell Lab of Ornithology, provides plans for bird boxes. You can also input your location and what’s around your house and find out if the bird you’re trying to attract might live in or near your yard. Info: nestwatch.org.
This story was originally published February 10, 2017 at 9:00 AM with the headline "Tips from an expert on how to build a proper birdhouse."