One Nestbox Bluebirds Like

One Nest Box Bluebirds Like

See the attached plans for one nest box which has received the "stamp of approval" from Eastern Bluebirds in Clay County, FL. You can also click here to see a 3D view of the finished product. Use your computer “mouse” to rotate the house to see the sides, top and bottom. The 3-D view of the bluebird nest box was created by Kyle Lamirande, Boy Scout Troop 279, Jacksonville FL, as part of an Eagle Scout project.  If the 3D view link doesn't work, you can download the 3D PDF file to your download folder and try to open it from there on your computer.  

Note that the opening in the door of the Florida bluebird box is precisely 1.5" inches in diameter. This is critical in order to keep starlings from taking over the nestbox. An oval hole 1 3/8"x 2¼" also can be used. It is easier to drill a round hole using a 1½" bit and also easier when placing a metal shield around the opening to discourage woodpeckers or squirrels from enlarging the opening.

A good floor size is 5"x5". Some plans on the Internet call for a 4"x4" floor. However, some people who maintain bluebird trails in Florida report better success with the 5"x5" floor size.

Of course, this is anecdotal, and lacks any scientific validity. Bluebirds may need as much ventilation as possible in Florida’s warmer climate.

The ¼" vent holes on the sides of the nestbox should be drilled at an upward angle to prevent water from running inside the nestbox during the torrential summer downpours which occur frequently in Florida.

The 9"x11" roof is good in Florida in order to provide more shade for the nestbox, to help prevent rain from blowing into the nestbox and to help prevent any animal that manages to overcome the predator guard from sitting on the roof and reaching into the nestbox.

Nestboxes preferably should be mounted on free-standing metal poles, such as the 1” metal conduit available at home improvement stores. In order to help guard against predation, nestboxes never should be mounted on trees, utility poles or fence posts. These mounts provide ready access for climbing or slithering nestbox raiders.

The bottom of the nestbox entrance opening should be no lower than 5’ above the ground. While bluebirds will nest in boxes lower or higher than that, this is a good height for being able to look into the nestbox during the weekly or twice weekly checks.

Attached are plans and a picture for a stovepipe predator guard intended to help prevent possible predators, such as snakes, raccoons, cats and squirrels, from climbing up the pole and getting into the nestbox. The predator guard is hung on a 3” long bolt slid through a hole drilled in the pipe just below the nest box. This allows the predator guard to swing freely.

No predator guard is 100 percent foolproof, and the one in the attached plans is no exceptions. On several occasions snakes have managed to climb up the outside of the stove pipe predator guard and devour the hatchlings in the nestbox.

Of course, a predator guard won’t stop airborne predators, such as the red-shouldered hawk, which is a familiar sight in Florida.

After You’ve Made the Nest box, Where do You Put it?

In Florida, bluebird nestboxes should be in place by the end of January.  This gives bluebirds time to inspect the nestbox before they start nesting the end of February or the beginning of March. In northeast Florida initial nesting activity usually begins the latter part of February.

The ideal habitat for Eastern Bluebirds is an open area with short grass that has been cut or mowed and has little or no underbrush.This includes areas such as golf courses, mowed meadows, cemeteries, open roadsides and open woodlands or orchards. There should be a perch nearby, such as a tree limb or overhead power line, where bluebirds can sit and look for insects, then swoop down on their prey.

Nestboxes should not be placed close to brushy areas, where they might attract predatory House Wrens, or close to trees or shrubs, where squirrels or cats could jump on them.

Nestboxes should be placed at least 100 yards apart. The North American Bluebird Society recommends nestboxes be placed 125 yards apart.  Also consider the “feeding area” when putting up a bluebird nest box. Bluebirds reportedly require a minimum of two to three acres to find sufficient insects to feed the ravenous nestlings.

The entrance hole should face away from the prevailing winds and towards a tree or shrub no more than 100 feet away so the fledglings can fly to them when leaving the nestbox.  It is important that fledglings have a place to fly to where they can be safe from ground predators, such as free-roaming cats.

OK, You’ve Put Up A Nestbox, What Now?

So, you’ve made an inviting box and put it in the right location. What next?  All you can do now is wait and see, like any "expectant parent."  Don’t be discouraged if bluebirds don’t nest in your boxes the first year you put them out.  Give bluebirds time to find them.  Some boxes have been installed for several years before bluebirds nested in them.  If your nestbox is in the right habitat and receives the bluebirds’ stamp of approval, don’t give up hope.  If they find your boxes and like them, they will take up residence.  In the meantime, other delightful and needy native cavity nesting birds such as the Tufted Titmouse or Carolina Chickadee might use your nestbox to raise a family. It usually takes bluebirds about five days to build a nest. A few days after the nest is completed, the female will lay one egg a day for about five days until she has a complete clutch (typically 4-5 eggs).

The female will not start incubating the eggs until the last, or next tolast egg is laid so that all the babies will hatch at about the same time. It takes about two weeks for the eggs to hatch.

The incubating period and first five days is a critical period in the lives of the hatchlings. Only the female bluebird has a brood patch and can incubate the eggs or keep the hatchlings warm during the first week of their lives. Should anything happen to the female during this period, the hatchlings probably will die. Should anything happen to the female after this period, the male bluebird may be able to successfully rear the nestlings if there is sufficient food available nearby.

Young bluebirds "fledge" from (leave) the nestbox when they are between 16 and 21 days old. The young birds still can’t fly very well and depend on their parents to feed them for several weeks.  Finally, when they are about a month old, the young bluebirds have earned their wings and are ready to take off on their own. Then the cycle may begin all over again, with the parents raising as many as three broods of birds in one season.

Do the same pair of bluebirds use the same nest box for the second and third broods?  To help answer this question, a pair of bluebirds raising nestlings in a particular nestbox on a trail in Clay County, FL., was banded.  The same banded pair of bluebirds later raised a second and third brood in the same nestbox.  In this instance the answer is, “Yes.”

If the parents really like your nestbox they could return to the area again the following year.  It has been estimated that approximately one-third of the bluebirds return to the same nesting site the following season.

If Bluebirds Do Their Part, You Must Do Your Part

Putting up a bluebird box is only the beginning. In order to have a successful, bluebird-friendly trail, nestboxes must be monitored regularly. It has been said that it’s better not to put up a nestbox at all than to put up a nestbox and not monitor it.

Why monitor a nestbox?For the benefit of the bluebirds and for your own satisfaction.

Nestboxes should be checked and cleaned out prior to the start of each nesting season.  This is the time to remove any mice, wasps or other unwanted “occupants” that would prevent bluebirds from using the nestbox.

Nestboxes should be monitored at least weekly and probably not more than twice weekly to determine the status of the birds and to insure that non-protected species, such as the House Sparrow, have not killed the bluebirds or driven them away.  If House Sparrows have taken over the nestboxes they should be destroyed before they can reproduce and cause further harm to bluebirds.

As a precaution when checking nestboxes, rap a couple of times on the side of the box, then stand to the side when opening the door, in order to give any "unwanted guests" the opportunity to get out.  Remember, not only birds sometimes may take up residence in a nestbox.  You also could find anything from snakes to mice and wasps or even a lone bat.  Bluebirds will avoid using – or even abandon – a nestbox which has been taken over by wasps.

Of course, other birds such as the Tufted Titmouse or Carolina Chickadees, might decide to nest in the box, also. These are protected, native species and cannot be disturbed.  You probably were hoping for bluebirds, but the nestbox is being used, and that’s what really matters.

Weekly monitoring also provides an opportunity to determine the condition of nestboxes, if nestboxes are being used, and the status of the nestlings.

Have squirrels or Red-Bellied Woodpeckers enlarged the entrance hole so starlings can get into the box?  If so, replace the door immediately, or put up a metal hole guard.  Has weathering caused any of the joints to separate, allowing rain to enter the box?  If the box is not occupied, repair or replace it immediately; if the nestbox is occupied place duct tape over the lose joint(s) as an emergency measure, then replace or repair the box after the young nestlings have fledged.

It also is important to keep an accurate record of the nesting activity.  Click here to see a sample monitoring sheet. Keeping a record is one way to learn more about bluebirds and their nesting habits.  The monitoring sheet will tell you which nest boxes are consistently active each season and which ones are not being used and need to be removed or moved to a different location. Keeping accurate records also will tell you when bluebirds begin nesting in your area, when the nests are completed, how many eggs are laid, how many eggs hatch, the age of the hatchlings, and how many hatchlings fledge.

Regular monitoring also is necessary to prevent nestlings from fledging prematurely.  The nest box should not be opened when the chicks are 14 days of age or older (unless you want experience rounding up frightened nestlings and insuring that they are returned unharmed to the nest and that they stay there until they calm down).

In Florida, Eastern Bluebirds can fledge through August.  After bluebirds have finished nesting it is time to prepare for the coming season.  This is a good time to inspect your nestboxes and make any necessary repairs. This also is the time you compile the data from your monitoring sheets and report the results to the National Phenology Network. Click here for instructions on creating an account and entering bluebird data on the National Phenology Network.  Entering the data will help both the Florida Bluebird Society and NPN learn more about the status of bluebirds in the Sunshine State.

If you’ve have had any unusual “learning experiences” while monitoring your bluebird nestboxes, or have any other interesting personal bluebird stories, tell the Florida Bluebird Society about them so they can be shared with other members.


  1. Jim & Evelyn McClung

    WE have blue birds returning for several years now. They seem to be populating. But now our multiple nest bird house is at a late stage of its useful life, and could fall off its perch anytime. It is not a blue bird house, but they seem to like it. They keep coming back. We need to locate a store that sales bird houses. Jim

  2. Bruce I Bartlett

    I started building blue bird boxes 20 years ago and now have put more than a dozen.I the state of Craftsbury Vermont.
    Now I have moved to Florida To do the same here

  3. Bruce I Bartlett

    Built Blue bird homes in Vermont 1998 and have over ten up and the birds been coming back for over10 years in East Craftsbury


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