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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.

BIRDS WERE TESTED BY A MARCH FREEZE

       The last thing we needed was extremely cold weather during the second weekend in March.  It would not have been so bad if one of the coldest days of the winter had not followed days upon days of temperatures hovering in the 70s and 80s. However, when I awoke on the morning of Sunday, March 13 the thermometer at my house read 24º F.  Not only did the late winter freeze threaten plants that had already begun blooming and/or sprouting leaves, it also endangered the lives of many birds.

       When the nighttime temperature drops this low untold numbers of birds face a life and death struggle to survive. A factor that often determines whether a bird survives to see the light of dawn is whether it is able to spend the night in a site that offers insulation from cold winds and low temperatures.  The warmer the site, the less energy it needs to burn simply to stay warm.

       For example, one of our common winter residents is the American goldfinch.  This gregarious bird roosts in dense vegetation.  If they are fortunate enough to roost is a location where the foliage and branches form a thick barrier against the wind and cold, they will burn about a third less energy than they would have expended had they been forced to roost in a more open site.

      All to frequently during extremely cold, windy weather birds roosting in unsuitable roost sites will literally starve to death during the night. For this reason, when you are trying to transform your yard into a haven for wildlife, do not overlook supplying your feathered backyard neighbors an abundance of suitable winter cover.

     Cavity nesting birds such as woodpeckers, nuthatches, Carolina chickadees, tufted titmice, and eastern bluebirds roost in natural cavities, nesting boxes, and roosting boxes.  The problem is, in most locales, the demand for these precious sites far outstrips their availability.

       The situation is often more dire for birds that roost in dense vegetation and brush piles.  The roster of these birds includes mockingbirds, yellow-rumped, and pine warblers, kinglets, sparrows, cardinals, dark-eyed juncos, blue jays and many others.  These birds roost in places such as evergreen shrubs and trees, as well as dense thickets and even brush piles.  Such sites are either woefully missing or in short supply in many neighborhoods.  Just a handful of these plants serve as safe havens for dozens of roosting birds. 

       Facing a paucity of places to escape the cold, birds will often attempt to find refuge in some odd places.  For example, when my daughter took the dog out a few hours after midnight on the 13th, she flushed a yellow-rumped warbler that had found refuge in the welcome wreath hanging on her front door.  Birds have been found roosting in other places such as inside open garages, barns and other buildings, above security lights, and on the limbs of Christmas trees.  

     A few of the native plants that address this need are red cedar, viburnums, wax myrtle, American holly and pines.

    With that in mind, if your yard lacks enough roosting cavities and/or evergreen trees and shrubs, make a point to add them to your landscape before our next cold front sweeps down from the north bringing with it freezing temperatures.  Hopefully, that will not happen until next winter.

    If you are looking for plans for a roost or nesting box, contact Melissa Hayes at the Georgia Wildlife Conservation Section (melissa.hayes@dnr.ga.gov).

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 NOVEL WAY TO KEEP FIRE ANTS OUT OF NEST BOXES

       Here in Georgia fire ants can threaten birds that nest in nesting boxes.  These pesky ants will enter nesting boxes and actually kill hatchlings.

       Several decades ago Jackson, Mississippi resident R.B. Layton came up with a novel way to keep these dreaded imported insects from reaching his nesting boxes.  Layton soaked either wood thread spools or sweetgum balls with the oil additive STP and placed them between the boxes and the poles that held them aloft.  Supposedly, this formed a barrier over which the ants would not pass.

       If you decide to try this technique, since thread now comes on plastic spools, you will have to find them at a craft store.  They are available in a variety of sizes.  I would imagine that you need to buy spools that are unpainted; an unpainted spool would probably retain more STP than those that are painted.  As for sweetgum balls, they can be located beneath sweetgum trees across the state.

       Since I have never had a problem with fire ants entering my nest boxes, I have never tested this technique.  However, if you try it, I would love to know if it worked for you.

BLUEBIRDS NEED WINTER ROOST SITES

        Since the weather has abruptly changed from being more like autumn than summer, my wife and I have been seeing eastern bluebirds inspecting some of our nesting boxes.  I am certain the birds are not checking out potential nesting sites–it is much too early for that.  The birds may be just curious, or perhaps the onset of cold nights has triggered a search for suitable roost sites.

       In addition to the bluebird, a number of familiar backyard birds also roost in cavities and nesting boxes including screech owls, woodpeckers, tufted titmice, brown-headed nuthatches, and Carolina chickadees.  In the case of the bluebird, they typically roost alone in warm weather.  However, when temperatures dip below freezing, a cavity or nesting box might harbor anywhere from a couple to more than 20 bluebirds. 

       The advantage of nesting together is the birds share their body heat.  During an extremely frigid night, the additional heat offered by a group of roosting birds may spell the difference between life and death.

       With that in mind, as we enter the harshest portion of the year, keep an eye on your nest boxes.  There is a good chance one more bluebirds or other cavity-nesting birds are roosting in a box erected to provide a place for them to nest.

       The best times to look for such activity is late in the afternoon when the birds are going to roost, or first thing in the morning when they are leaving for a day of foraging.

       You can also peek inside a box.  If you see some downy feathers scattered about the bottom of a box, chances are birds are roosting there.

BLUEBIRD BOX COLOR IS IMPORTANT

        Cavity nesting birds have a difficult time finding a place to nest.  In fact, there simply aren’t enough suitable cavities to meets the needs of the birds that need them.  Throughout Georgia a wide assortment of birds nest in tree cavities including the eastern bluebird, Carolina wren, house wren, house sparrow, tree swallow, European starling, purple martin, barn owl, tree swallow, screech owl, great crested flycatcher, Prothonotary warbler, and wood duck.  In an attempt to offset the shortage of natural cavities, for more than eleven decades folks have been building and erecting nesting boxes.  Beyond a shadow of doubt more nest boxes have been built for bluebirds than any other species. They have been so successful they have played a large part in the recovery of this beautiful bird.

       While the majority of bluebird nesting boxes look pretty much the same, some provide better nesting sites for the birds than others. Often the only thing that determines whether or not a box is better than another is its color.

       Bluebird nesting boxes are painted in a rainbow of colors. In fact, I once saw a black bluebird nesting in a blue bluebird box. I would like to know how many red and black See Rock City have been erected across the south. Some folks paint nesting boxes in the colors of their alma mater or favorite football team. Others leave boxes unpainted. With this bewildering array of colors to choose from, you might be wondering what works the best. In truth, bluebirds don’t seem to show a preference for any color.  However, studies have shown that year in and year out more bluebirds fledge from boxes painted certain colors over all others.   Let’s take a look at what’s best for the birds and your pocketbook.

      Most store-bought bluebird boxes are unpainted.  Typically, they are made from finished pine boards.  If you take such a box home and hang it out without doing anything to it, chances are it will rot in a season or two and end up lying on the ground. Consequently, if you want the box to last a lot longer, coat it with a good quality exterior paint or stain before you put it up.  When you treat a box in this manner, it will last several years.  With most bluebird boxes costing anywhere from $10-$25 or more, this is a significant savings.

       However, boxes made from cypress or cedar should not be treated. These woods naturally resist decay.  It is not unusual for a well-made cypress box to last up to 25 years.

       Here in the South, it is best to paint boxes a light color.  Any light color is suitable. Bluebirds don’t care if a box is white, gray, light pink or pale blue.  However, whatever you do avoid using dark colors.  The reason for this is simple, pastel colors absorb less heat than boxes coated in dark colors.

       Here in the Peach State during the spring and summer (the bluebird’s nesting season), the thermometer often soars above 90°F.  However, when air temperature reaches only 87°F, the temperature inside a nesting box painted a dark color can soar to 107°F or more.  When eggs are exposed to such intense heat, developing bluebird embryos can be killed.  Bluebird eggs seem to develop best when temperatures inside a box are no higher than 99°F. 

       When painting a box, I prefer using an oil-base exterior paint. You will find it will last longer than other exterior paints.  I ALWAYS avoid lead-based paints since there is always the potential that birds and other wildlife can ingest paint chips containing lead.

       It is always best to paint a box before it is erected. Use a medium-sized flat brush. Apply at least one coat of paint to all exterior surfaces. If the bare wood absorbs a lot of paint, apply a second coat.  I would recommend that you apply 3 or more coats of paint to the back of the box. Since this surface will be in direct contact to a tree, post, or metal pole, as such it will be exposed to water much longer than the other surfaces of a box.  The extra paint provides an added barrier to water.

       Under no circumstances should you paint the interior of box or its entrance hole. In fact, I recommend that you avoid using spray paint since there is always a possibility that paint can be accidentally sprayed inside the box.

       Isn’t it amazing how a little dab of the right color paint can be so important to such a gorgeous and popular bird?

SHOULD I CHECK MY BLUEBIRD BOXES?

       With bluebirds now nesting across the state, I am often asked, “Should I check my bluebird boxes?”  When this question is posed I always tell folks that, if it done properly, checking bluebird nesting boxes can actually be beneficial to the birds.  Let me explain.

       Unlike many birds, the eastern bluebird is more tolerant of human activity around their nests than many other birds.  This tolerance allows the close monitoring of the success of the birds’ nesting efforts.  By so doing we can help thwart situations that can lead to the failure of a nesting attempt. 

       For example, we can keep house sparrows from taking over a box by tossing out the sparrow’s bulky nesting materials.  If this is done enough times, the aggressive, unprotected, invasive house sparrows will finally give up and leave the box alone.

       (Never remove the nest of a native cavity-nesting bird.)

       Also, wasps will occasionally attempt to build a nest on the underside of the top of a box.  If wasps are allowed to build a nest inside a box, bluebirds will abandon it.  With that in mind, if you find a small wasp nest, remove it. 

       If you plan to monitor a box, make sure the box can be easily opened.  Too often boxes are made in such a way that the box cannot be opened from the top or side.

       Make every effort to make nest box checks as brief as possible.  In addition, it is always best to check boxes when temperatures are mild, winds are calm, and it is not raining.

       Checks can be safely performed weekly up until the hatchlings are 12 or 13 days old.  Checks made after that time can result in the youngsters prematurely bailing out of their nests.

       If you monitor you boxes on a weekly basis, you will know when a nest is built, when a female lays all of her eggs (females lay one egg a day until the clutch is complete), incubation has begun, the approximate age of the hatchlings, and how many young bluebirds successfully fledge.

       Here are some facts that will help you understand what you will be observing.  Typical clutch size is 4-5 eggs; Incubation lasts 12-14 days; Time of fledging: anywhere from 17-21 days.

       The North American Bluebird Society recommends the nest be removed after the young fledge.  If a bluebird wants to use the box later, a new nest will be constructed in short order. 

       However, dispose of the old nesting materials some distance from the nest site.  This will help keep potential predators from discovering the location of the nest.

       Keep in mind, eastern bluebirds will nest up the three times a year.

       If you have additional questions about checking, please let me know.

NOVEMBER IS A PERFECT TIME TO PUT UP A BIRD BOX

       I would venture to say most people would not think of putting up a bird box in November.  However, if you stop and think about it, it is the perfect time to take on this labor of love.

       This is a great idea because cavity nesting birds such as eastern bluebirds, Carolina chickadees, tufted titmice and the like use tree cavities and nest boxes for roosting and nesting.  Consequently, by erecting a box at this time of the year you box will serve as a winter roosting site and be available for nesting next spring.

       There are rarely enough winter roost sites available for the birds that use them.  Take eastern bluebirds, for example.  At this time of the year, your neighborhood can serve as the winter home for adult bluebirds that nested this year, their young and migrants from points north.

       The ability of cavity nesting birds to find a winter roost site prior to a frigid winter night can be critical to their survival.  Those that cannot locate such cover stand the chance of freezing to death before morning.

       If you are going to erect a new box, here are a few things you can do to make it a bit cozier for winter occupants.  First, place an inch or so of dry wood chips or dry grass in the bottom of the box. 

       Some folks even go to the trouble of covering the bottom of the box with a piece of Styrofoam.  If you do so, bore a few holes in the Styrofoam for water to drain out of the box.

       Another modification you might consider is plugging the box’s vent holes this prevents warm air from escaping the box.  If you add a piece of Styrofoam and/or plug the vent holes, remove the insulation before spring.

       You can also drill a couple of holes on either side of the box.  A wooden dowel can be inserted through the holes.  By so doing, you are providing roosting birds with a perch.  At the end of the winter, the dowel can be removed before nesting season.  Since upwards of 20 or more birds will sometimes roost in a bluebird nesting box on a cold night, the dowel will make it more comfortable for the birds escaping the cold.

       If you are curious as to whether or not your box is being used as a winter roost site, simply inspect it for signs of use.  If birds are roosting there, they often leave behind feathers, droppings, and sometimes food.

       A word of caution: do not check a box at night.  Birds disrupted during the night will often stop using the box from then on.

       Finally, before putting up a box, place a metal hole guard around the entrance hole.  This prevents squirrels from enlarging the hole and ruining the box.

A BLUEBIRD NESTING SITE LIKE NO OTHER

BLUEBIRD BOX ON BOTTLE TREE

 

Over the years, I have encountered eastern bluebirds nesting in a variety of locations, however, recently I was shown a bluebird nesting site like no other.  Beyond a shadow of a doubt, it is the most colorful and unique nesting location I have ever come across.

This nesting box is situated in a forest of trees.  This is not a forest of pines or hardwoods; this forest is composed of a kaleidoscope of more than 140 bottle trees.  Dr. Jerry Payne, the creator of this fanciful forest, has dedicated one of his beautiful creations to the eastern bluebird.  Bluebirds must have found this special tree as pleasing to their eyes as we do.  During each of the three years the box has hung on a bottle tree nestled between  an array of colorful bottles, bluebirds have successfully fledged young.

If you have encountered an unusual bluebird nesting site, I would like to hear about it.

HOLE GUARDS ARE A MUST FOR NESTING BOXES

        If you erect bird nesting boxes, invariably there will come a time when a woodpecker, gray, or flying squirrel takes it upon itself to enlarge the entrance hole on one of your bird boxes.  When this happens the perpetrator might enlarge a 1.5-inch entrance hole to one that is now is 3-4 inches in diameter.

       Whenever a bird or mammal remodels the entrance hole in a nesting box, the structure is often destroyed or, at the very least, puts any bird that tries to nest in the box at risk.

       A bigger hole allows larger birds to nest in the box.  Most boxes erected in Georgia are designed to help alleviate the eastern bluebird’s housing shortage.  A box equipped with a 1.5-inch hole, prevents larger, more aggressive European starlings from nesting in the box.  Without such protection, bluebird numbers would plummet.

       A larger hole also allows nest predators such domestic cats, raccoons, and even opossums to reach into a box and snatch out nesting adults, their eggs, and young.

       I have found that one of the best ways thwart unsolicited attempts to alter the size of entrance holes is to equip nesting boxes with a simple, inexpensive device called a hole guard.

       The hole guard is nothing more than a piece of metal that is attached around the entrance to a nest box.  They are available in various sizes.  For example, if you want to encourage birds the size of a bluebird or smaller, install a hole guard featuring a 1.5-inch opening.  Likewise, if your goal is to encourage smaller birds, such as Carolina chickadees to nest in your boxes cut a one-inch entrance hole in your box and protect it with a one-inch hole guard.

       Believe me these simple devices work. In fact, they are so effective, I will not erect a new box without one.

       In all the years that I have used them, I have seen a hole guard fail only once.  In that case, the hole guard actually worked, however, an unknown critter almost totally destroyed the entire box. In spite of this all out attack, the hole guard remained in place.

       Hole guards can be purchased are stores that specialize in birds. If you try one, you will not be disappointed.

      

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