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DO EASTERN BLUEBIRDS USE THE SAME BOX FOR MORE THAN ONE YEAR?
If you erect bluebird boxes, more than likely you have wondered if bluebirds return to nest in the same nest box they used the year before.
As it turns out, banding studies demonstrate anywhere from 26-44% of the bluebirds that nested in box last year will return to nest there this year.
One factor that determines if bluebirds use the same box from year to year is whether their nesting efforts the previous year were successful. As you might imagine, they are more likely to use the same box if they successfully raised young in that box the previous breeding season.
BEST TIME TO CLEAN BARN OWL BOXES
If you erect and maintain nesting boxes for birds in your yard, you realize the need to annually repair and clean them during a time when birds are not nesting. This is easy to do because the nesting dates of most birds that nest in our backyards are well known. However, if you have a barn owl nest box on your property, you have a problem. It seems that biologists know surprisingly little about when barn owls nest in Georgia.
Such is not the case in California. Researchers at the University of California, Davis combed through almost 100 years of banding and other records to determine when barn owls nest in California.
The biologists found that the median egg laying date in California is February 20. Consequently, the lead author of the study Ryan Bourbour says, “We want to reduce disturbances to breeding pairs prior to egg laying.” Based on the findings the researchers recommend boxes need to be erected, repaired, and cleaned in the fall.
Unfortunately, the only nesting records for Peach State barn owls are largely anecdotal. Only a dozen barn owl breeding records surfaced during The Breeding Bird Atlas of Georgia Project. Although most records came from central Georgia, breeding was corroborated from the mountains to the coast. Undoubtedly, barn owl nesting is more common and widespread in all parts of the state.
In Thomas Burleigh’s book Georgia Birds, the author noted that nests have been located from March to December. However, biologists do not have enough data to develop a median egg laying date for Georgia.
Since we know there is a need to provide more nesting sites for barn owls in Georgia, we all need to check our barn owl boxes during each season of the year. When we conduct a check, if no nesting is currently going on, we need to repair and clean it. If nesting has or is taking place since the last check, record it too. Over time, we should be able to determine when nesting takes occurs in our part of the state.
If you don’t have any barn owl nesting boxes on your property, consider erecting one. Once you have one in place, follow the procedure outlined above.
It would be great if landowners knew when it is the best time to conduct an annual barn owl nest box check.
Let me know what you find. I will forward your information on to the Wildlife Conservation Section biologists trying to restore nongame wildlife throughout Georgia. Hopefully, your information will enable them to establish a median egg laying date for Georgia and recommend the best time to check barn owl nesting boxes.
REDUCE COMPETITION FOR NEST BOXES BETWEEN CAROLINA CHICKADEES AND BLUEBIRDS
Since there is a paucity of natural bird nesting cavities throughout Georgia, Carolina chickadees often have to compete with eastern bluebirds for the same nesting boxes. When this occurs Carolina chickadees usually end up looking for another place to nest. There are, however, ways in which you can provide a nesting site of Carolina chickadees.
One approach is to equip a nesting box with an 1 1/8-inch
entrance hole instead of the 1½-inch hole featured on standard bluebird boxes—bluebirds simply cannot squeeze through a 1 1/8 –hole.
However, Carolina chickadees can enter nesting boxes 1 1/8 inches or larger in diameter. Consequently, even if a pair of Carolina chickadees begins nesting in a standard bluebird box, the pair is not guaranteed their nesting attempt will be successful.
One reason for this is bluebirds will actually run off chickadees even after they have begun nesting. It has also been documented that bluebirds will deposit their own nesting material over Carolina chickadee hatchlings.
With that in mind, consider dedicating one or more nesting boxes for Carolina chickadees. If Carolina chickadee nesting boxes are not readily available in your area, and you don’t have the means to build your own box, all you have to do is install a metal hole guard featuring a 1 1/8-inch hole over the 1½ hole cut in the box. Problem solved.
IT IS TIME TO REMOVE VINES AND TALL PLANTS GROWING NEAR NESTING BOXES
Before we know it, spring will be here, and birds will be nesting in the nesting boxes we have erected for them. Among the chores we all need to tackle in preparation for this year’s nesting season is trim back the vines, saplings and shrubs growing close to each of our nesting boxes.
One of the main reasons why this should be done is it helps protect the birds nesting in our boxes from arboreal snakes (those that climb trees). Snakes such as the rat snake are capable raiding nesting boxes erected on poles. For that reason, it is always best to mount nesting boxes on poles equipped with predator guards. However, even the best predator guards cannot protect a nest if vines encircle the pole or tall vegetation is growing nearby. Such plants create a veritable superhighway for snakes trying to raid a nesting box. Even if vegetation is not actually touching a box or pole, a snake can circumvent a predator guard and gain access to adults, eggs and/or young birds by simply climbing up nearby vegetation and then extending their body the distance between their head and the box.
For this reason, we need to make every effort to cut back tall vegetation in a wide circle around each nest. While we are creating this protection zone, any branches growing close to the top of the box should also be trimmed away. Snakes are also capable of using a canopy of branches to gain access to a nesting box.
Taking a little time to perform this simple task can give the birds nesting in our boxes a better chance of being successful.
A BEAUTIFUL PLACE FOR BUMBLEBEES TO SPEND A COOL FALL NIGHT
The Confederate rose brings spectacular beauty to yards across Georgia. However, my wife, Donna, and I have found that its showy blossoms are also used as places for bumblebees to escape the cold on chilly autumn nights.
This large multi-stemmed shrub or small tree was brought to North America in the 1600s. Since then it has been widely planted throughout the Southeast. It popularity stems from the fact that, from late summer until frost, it bears scores of white blossoms that measure up to six inches in diameter. These flowers eventually turn light pink before finally becoming rose-colored.
While my wife and I thoroughly enjoy the beauty the flowers bring to our yard, our discovery that these stunning blooms provide bumblebees with warm refuges on chilly fall nights has heightened our appreciation for the plant.
For quite some time, I had not given any thought to this interesting behavior until late one afternoon this past week. Late one afternoon I noticed that my wife, was looking deep into the one of the blossoms adorning a Confederate rose growing alongside our driveway. I walked up to find out what had caught her attention. When she said she was looking at a bumblebee that had settled in for the night deep inside a Confederate rose bloom, I peered down into the throat of the flower and spotted the insect. As we stood nearby discussing her find, a couple of other bumblebees flew into other blossoms.
When I returned to the flowers well after dark, sure enough, the bumblebees were still there awaiting morning when temperatures warmed to the point where they could utilize the muscles that control their wings and fly away.
A number of animals seek cover on chilly nights. Many birds and mammals retreat to natural cavities, nesting boxes, thick vegetation, and other places. However, I doubt that many spend cold nights nestled in cover as beautiful a Confederate rose blossom.
If you have a Confederate rose growing in your yard, before the blossoms nipped by a frost, as the sun is setting check them out. If bumblebees are still flying about in your neck of the woods, chances are one or more might be using some of gorgeous blooms for nighttime cover also.
MORE NEST BOX INFORMATION
In response to the recent blog regarding the placement on birdhouses in backyard settings, one of our fellow bloggers requested information concerning the minimum size of entrance holes recommended for the species mentioned. Realizing many others might have the same question, below you will find this information. In addition, I have included the recommended minimum height a box should be placed above the ground for each of these eight species.
| Species | Minimum Hole Size | Height Above Ground |
| Eastern Bluebird | 1.5″ | 5′ |
| Carolina Chickadee | 1 1/8″ | 5′ |
| Tree Swallow | 1 3/8″ | 5′ |
| Tufted Titmouse | 1 1/8″ | 5′ |
| Carolina Wren | 1.5″ | 5′ |
| House Wren | 1 1/8″ | 5′ |
| Great Crested Flycatcher | 1.5″ | 6′ |
| Brown-headed Nuthatch | 1 | 5′ |
BIRDHOUSES ARE OFTEN PLACED TOO CLOSE TOGETHER
Nesting birds are often very territorial. As such, when one pair spots another pair of the same species trying to nest too close to their nesting site, conflicts emerge. With that in mind, one of the reasons why birds do not use birdhouse in some yards is boxes are placed too close together. When nesting boxes are packed in too closely, some birds of the same species will fight with one another and sometimes end up not nesting at all.
NESTING PAIR OF BLUEBIRDS
With this in mind, here is a list of some of the birds that commonly nest in Georgia backyards and the recommended spacing between boxes designed avoid territorial battles.
Eastern Bluebird – Minimum of 100 yards.
Carolina Chickadee – 30 feet
Tree Swallow – 35 feet
Tufted Titmouse – 580 feet
Carolina Wren – 330 feet
House Wren – 100 feet
Great Crested Flycatcher – 1 box per 6 acres
Brown-headed Nuthatch – 1 box per 6 acres
Keep in mind that some species tolerate birds of another species nesting close to their nest. For example, eastern bluebirds will allow Carolina chickadees to nest well within 100 yards of their nests. In this case, if a Carolina chickadee nest box is equipped with an entrance hole measuring 1 1/6th of an inch in diameter, bluebirds would never try to nest in a birdhouse with an entrance hole that small.
TUFTED TITMICE NEED PLACES TO NEST TOO
Like all cavity nesting birds, rarely are their enough places for tufted titmice to nest in most neighborhoods. With that in mind, if your property is predominantly wooded, why not erect a nest box for one of our favorite backyard feeder birds?
If you think you would like to take on this project, here are a few tips that will help enhances the chances your efforts will be successful.
I would recommend that you start putting up a single box. If a pair of titmice uses it, consider erecting another birdhouse. However, since tufted titmice are territorial, it is best to space your boxes at least 580 feet apart.
The diameter of the box’s entrance hole should be at least 1 3’8″. As you might expect, the birds will nest in cavities with larger entrance holes such as the 1 1/2-inch hole recommended for bluebird boxes. Whatever size you use, protect the entrance hole with a metal hole guard. This simple device prevents other birds and mammals from increasing the size of the entrance hole. If you don’t, more often than not, their handiwork will end up destroying the box.
Titmice will nest in cavities as high as 87 feet above the ground. However, I recommend that your box be placed about 5 feet high. This allows you to safely check, clean, and maintain it.
I hope you decide to erect a tufted titmouse nesting box this year, if you do, you will help alleviate a shortage in tufted titmice nesting sites. In addition, you will benefit by being able see tufted titmice as well as hear their pleasant peter, peter, peter call more often from spring through winter.
A SIMPLE WAY TO WINTERIZE A BLUEBIRD BOX
Although those of us that live in Georgia do not have to withstand the bitter cold that winter brings to the northern sections of the country, it still gets mighty cold in these parts.
When temperatures plummet into the 20s and below, simply trying to stay alive on a frigid winter night can be a life-threatening event for many of our wildlife neighbors. One way in which we can assist birds such as bluebirds that roost in nesting boxes survive extremely cold weather is by winterizing nesting boxes.
If you have erected a well-built nesting box, it is equipped with several 3/8″ ventilation holes drilled under the eaves of the box’s roof. These vent holes are designed to dramatically reduce the temperature inside the box in hot weather. However, during the winter vent holes allow heat to escape.
With that in mind, it is a good idea to plug these holes before the onset of winter. By so doing, you will increase the amount of heat retained in a box.
Now that most of us are getting our first taste of cold weather, there is no better time to perform this simple task than right now.
When the last threat of severely cold weather has passed next year, do not forget to unplug the vent holes.