By Terry W. Johnson
The winter of 2009-2010 is one we will long remember. Snow has blanketed the state from Rising Fawn to the peanut fields of South Georgia. If that wasn’t enough, temperatures have plummeted into the teens. This caused the cost of heating our homes to soar skyward faster than our national debt. Homeowners who had the foresight to winterize their homes by caulking the cracks around windows and doors, and took other measures to reduce heat loss, actually are being rewarded with lower energy bills.
When the cost of heating our homes was low, we just didn’t give it much thought. One of our backyard neighbors, the brown-headed nuthatch, however, has been caulking the cracks in its nesting sites for generations. Although nobody knows exactly why these tiny birds perform this annual ritual, some biologists suggest that since nuthatches nest late in the winter when arctic weather is still a possibility, this natural weather stripping helps keep eggs and hatchlings warm on even the coldest days. Who knows?
The brown-headed nuthatch prefers to nest in tree cavities. However, like all cavity-nesting birds, they have long suffered from a housing shortage. Fortunately for the brown-headed nuthatch, it has found nesting boxes to its liking. Additionally, it doesn’t mind nesting close to our homes. This has allowed nuthatches to live in places where they would have disappeared long ago.
The brown-headed nuthatch is one of the first of our cavity nesters to nest. In fact, they will begin checking out potential nesting sites as early as February in much of the state. While you may not see nuthatches inspecting your nesting boxes, they will leave clues that reveal they have made an inspection trip to your backyard.
Closely examine the joints between the boards used to build your nesting boxes. If you see bits and pieces of pine straw and other plant materials stuffed into the cracks, you know a brown-headed nuthatch has been there. Since not all brown-headed nuthatches seal their nesting sites, not finding their weather stripping doesn’t necessarily mean the birds won’t use your boxes.
Should you be lucky enough to have a box used by a pair of brown-headed nuthatches, you are in for a real treat. You will have the rare chance of watching their unusual nesting and feeding behavior.
If it isn’t too late, you will see them inspect nesting boxes. If one is found suitable, you will watch them diligently weather-strip it. Their next job is to construct a small nest. The birds build their nests out of strips of the inner bark of trees, plus grasses, wood chips, hair and feathers. Their nests also typically contain the wings and husks of pine seeds. In fact, occasionally you will discover a nest made entirely of this unusual nesting material. If you watch the birds closely as they return to their nest site with nesting material, you may be able to tell what they are using.
The female lays three to nine white eggs adorned with fine reddish-brown spots. Incubation is performed solely by the female and lasts about 14 days. Although males choose the nest site, they don’t help with this arduous task. Instead, he will roost beside her at night and even bring her food while she is nesting. For some odd reason, sometimes one or more other nuthatches will commonly aid in nesting duties. These helpers are often young males. While it is thought that they are older offspring, nobody knows for sure.
The young grow rapidly on a diet of pine seeds, cockroaches, beetles and other insects, as well other delectable six- and eight-legged critters and their eggs. In only 18 days the youngsters are ready to take wing.
It is fun to watch these tiny birds find food and feed it to their youngsters. The energetic adults fly from tree to tree chattering as they look for food. One minute they might be inspecting pinecones; the next, hanging upside down to peer under the scaly bark of a tree. If you watch them carefully and are real lucky, you might just observe the rare use of a tool by a bird. Believe it or not, brown-headed nuthatches have actually been seen using a small piece of bark as a pry bar. They use it to raise up bark in their search for food. They will even carry their “tool” from tree to tree.
Nesting boxes specifically for brown-headed nuthatches are equipped with an entrance hole measuring 1¼-inch in diameter. A hole this small keeps larger birds from competing for hard to find nesting sites. Unfortunately, few folks erect nest boxes with brown-headed nuthatches in mind. As luck would have it, these birds will also nest in bluebird boxes sporting 1½-inch entrance holes.
Your chances of attracting a pair of brown-headed nuthatches to your yard are greatly enhanced if your backyard is blessed with scattered pines. Unlike many cavity nesters, they will nest in boxes in the shade.
While nuthatches will nest in boxes constructed of finished lumber, some suggest that they prefer boxes made from rough-hewn lumber. I always place 2 to 3 inches of dry sawdust in the bottom of each box to make the box appear more natural. However, they will build their nests in boxes that lack sawdust.
Ideally, boxes should be mounted at least five feet above the ground on poles equipped with predator guards. Boxes should be at least eight feet from a tree or other cavity. If you would like plans for a brown-headed nuthatch nesting box, visit this page on the Wildlife Resources Division Web site.
However, don’t procrastinate; you need to erect the box ASAP. Remember, brown-headed nuthatches are either looking for nesting sites or nesting right now!
Terry Johnson is a former Nongame program manager with the Wildlife Resources Division, a backyard wildlife expert, and executive director of TERN, the friends group for Wildlife Resources' Nongame Conservation Section. Terry’s column is a regular Georgia Wild feature.