Eastern Bluebird

Wood Thrush Notes

Earliest Bluebird Nest with Eggs

Wood Thrush Shop team member, Jan, reported 5 Bluebird eggs in a nestbox at her home on Friday of this week.  Wow, that’s early!  This means the first egg was laid on the 4th of March and actual nest building was likely occurring in February, although Bluebirds have been known to sometimes build a nest in a day or two.  This is an eager pair of Bluebirds.  Jan had an early nesting last year, too. For most of us seeing Bluebirds nesting is still probably a couple of weeks away, if not longer.  Many Springs I haven’t seen a 1st Bluebird nesting in my yard until well into April.  Remember, they all do not start at the same time so there is no need to be concerned that you have done something wrong because you haven’t seen evidence of nesting yet.  And, there’s a lot of time still to present a new Bluebird box and have success this spring and summer.

Should I Offer Mealworms to Bluebirds?

Offering mealworms is not necessary to attract Bluebirds.  Offering a couple of nestboxes and birdbaths in good locations is the most important factor.  Insects, the primary food source of Bluebirds, are everywhere they travel, Bluebird boxes are not.  My advice is to start with the nestbox first.  At such time Bluebirds discover the nestbox and begin nest building, or even egg laying, and if you are interested in feeding this is a good time to start.  I think the following tips are the best way to begin feeding Bluebirds:

  • I would not recommend presenting mealworms before Bluebirds have begun nesting.  You may just end up feeding other birds, which is ok, however, if you are presenting the worms near the nestbox birds like Robins, Mockingbirds, Jays, and Cardinals may become very territorial and aggressive about the free and easy food source.  These birds may swoop in and drive the Bluebirds from the nestbox. 

  • Let’s say Bluebirds have built a nest and eggs are present.  How do you know?  Refer to our website and the Bluebird section about monitoring.  It is best to start by offering small amounts of worms, a dozen or so, and make sure the Bluebirds are near to see you place the worms in the feeder. My favorite feeder is a ceramic dish on a stand just 18” off the ground.  As feeders go simple is best, dishes and platforms.  If you feed Bluebirds the way we recommend you will not have to contend with larger birds becoming an issue and then need a specialized Bluebird feeder.  Now walk away and watch.  If the Bluebirds immediately pounce on and eat the worms offer another small helping to reinforce the process.  If they fly away remove the worms so other birds do not find them and try again later.  The goal is to establish you as the “keeper of the worms”.  Three or four successful feeding sessions and they will begin associating you with the treat.  Some people like to make a noise each time they offer worms so eventually Bluebirds will key in on the sound, like the Pavlov’s dogs experiment. I prefer silence because other birds are smart enough to key on the noise, too.

  • Live mealworms are always more appealing than dried, no contest, especially in spring and summer months. In warm weather live insects are readily available so dried mealworms tend to be less appealing. 

Follow these tips and you will have a good Bluebird feeding experience.  And do not feel as if you must feed them several times a day, or be concerned if you go on vacation and they won’t get worms for a week.  Bluebirds know what they are doing and will not become dependent on the worms but only take advantage of them. 

Next Week.  When Should I Put out a Hummingbird Feeder?

Get Ready for Bluebirds Now

In the coming weeks we will be sharing information about Bluebirds.  We would like to address specific questions and concerns you may have that can then be shared with everyone.  If you have questions regarding Bluebirds please email us at thewoodthrushshop@gmail.com and we’ll provide answers in our weekly blog, or directly back to you in an email.    

Birds are beginning to sing and exhibit other courtship behaviors. The breeding season is fast approaching.  Eastern Bluebirds have already begun searching and competing for mates and potential nest-sites.  If you had planned on replacing an old nest box or moving one to a new location we suggest you do it now. And make it a point to clean out old nests now.  Old nests will not prevent a Bluebird from building a new nest on top, however, the old nest debris is by now decaying and damp and can be a home to insects, like ants, which can be of great harm to hatched chicks.   

Many of you in past weeks have seen multiple Bluebirds land on and look in nest boxes. (See video) In the video you will see classic courtship behaviors like wing fluttering. They may even carry some nest material to the box.  This is not actual nesting but all part of courtship and choosing a nest site which the female will eventually approve. 

Although most Bluebirds won’t begin their first nesting until early to mid-April, their search for nest sites will typically intensify in the last weeks of February and into March.  Some eager Bluebirds may begin nesting as early as mid-March.  

You may think you don’t have the right situation for Bluebirds because you’ve heard they have very specific needs for successful nesting.  The most common fallacy we here from people is “I hear they need wide open spaces”.  This is definitely not true.  In fact, a lot of what you hear about the needs of Bluebirds is very much over stated.  Bluebirds adapt very nicely to all kinds of situations including wooded yards.  If Bluebirds needed the “perfect setup” as described by the many articles you find on the internet they would be extinct by now. These perfect nest-sites generally never existed in nature and have only been determined by humans.

In fact, before people started putting out nest-boxes for Bluebirds they nested in natural cavities including ones in trees. Bluebirds are considered a secondary cavity nester which means they will not excavate a nest, like a woodpecker does, but use one that has already been created.  Once upon a time secondary cavities were in great supply but through habitat loss and competition Bluebirds were “forced” to adapt to birdhouses, or what we refer to as nest-boxes.  Using nest-boxes is an example of Bluebirds’ adaptability.   Offer a couple of nest-boxes in good locations and see what happens.  

 Here are a Few Tips to Choose a Location:

  • Position the nest box adjacent to the most open location available in your yard.  Trees being around or close by are not a deterrent.

  • Bluebirds are typically more sensitive to nesting near a lot of bird traffic, so it’s not recommended nest boxes be placed near bird feeders.  What’s a comfortable distance?  It’s impossible to be exact but we would suggest about 100 feet away, or out of sight of feeding stations. 

  • You may have heard that nest boxes need to face east.  This is a good strategy to avoid prevailing weather patterns and rain but not at all necessary. My most successful box over the years faces northwest. 

  • A Bluebird box does not need to be on a pole. The advantage of a pole is it allows you to position the box in the location you determine to be the best.  Our pole system for Bluebird boxes will put the box at 5’ high after installation (convenient for monitoring and maintenance) and allows for a baffle if you’ve had a history of raccoon or rat snake predation.  Bluebird boxes can be mounted on fences, and utility poles, and even outbuildings. The National Bluebird Society changed their opinion about tree mounting only a few years ago.   Obviously a tree is a more vulnerable location when considering predators.

  • How many boxes can be offered in a typical yard situation?  There is no harm in offering lots of nest boxes (birdhouses) in your yard but do not expect them to all get used at the same time especially if they are close in proximity to one another.  In most cases backyard songbirds are too territorial to tolerate nesting close to one another, unless they are colony nesters like Purple Martins.  But feel free to decorate your yard with lots of birdhouses if that’s your thing.  Offering multiple nest-boxes is great and it does lessen the competition for a single box but do consider the nature of the species you are trying to attract and what kind of setting would be most appealing.

  • We are often asked “when is a good time to put up a bluebird box”?   Every day is good.   However, it is a great time to do so in the next few weeks. The sooner they know the box is there the more likely they will consider using it this season.

Get busy now and have fun with attracting Bluebirds this spring and summer.

Monitoring Bluebird Boxes

It’s great that so many people are interested in providing nest boxes for Bluebirds, and because of these efforts Bluebird populations are extremely robust. We encounter customers, though, that ask a lot of questions they would have the answer to if they just monitored the nest box a little. We do not mind answering the questions, it’s very much part of the job.

Most of the time when we mention to a customer they should consider monitoring the box their response is “I don’t want to disturb them or scare them away”. If done properly neither of those things will happen. Not only is it interesting and a great nature and biology lesson, you can predict within a day or two when the babies will leave the box. And another reason to monitor is you may actually keep something bad from happening to the babies. I’ve often told customers of the time my son, who I taught to monitor, discovered one of our boxes with four two day old Bluebird babies was infested with ants. In just 48 hours, since the last monitoring, ants had found the newborn babies and were likely going to consume them given enough time.

We carefully removed the babies and placed them in a little box, then removed the entire nest from the box while the female watched from a nearby tree limb. We first cleaned all the ants out of the now empty nestbox and made sure no more would climb the pole. Then we constructed a rather poor replica of the nest using their preferred nest material pine straw. After the nest was back in the box we then removed all the ants from the babies by using a drinking straw to blow the ants off and then placed them back in the box in the clean nest. In all it took us about 20 minutes. The female returned to the box about 10 minutes after we completed the cleaning. Even after removing the nest and handling her babies the female came right back to them because the instinct to raise her young is that powerful. So, monitoring which really just consists of taking a peak for a few seconds will definitely not scare the birds away. Bluebirds tend to be quite tolerant of our presence. Usually they patiently watch as I monitor. Once in a while they will swoop at you clicking their beak in protest. But they will not abandon a nest because of brief looks in the box.

Monitoring Tips

  • Observing from a distance is important monitoring, too. Seeing bluebirds come and go is an indication they are showing an interest in choosing the box. If you see the pair on and in the box take a moment after they leave to go look inside. You will likely observe nest building at some point. Pine straw and fine dry grasses are the preferred nest material.

  • Bluebirds tend to lay eggs in the morning hours. The female will lay one per day until done, usually between three and six. Four and five eggs seem to be the most common numbers. She will not begin incubating until all the eggs are laid. So, at this stage I would recommend monitoring in the afternoon so as not to disturb egg laying in the morning. Or, again, if you see the female exit the box take a moment to go look. Take notes. It’s helpful to increasing your knowledge of the process.

  • When I monitor and see 4 eggs and she is not incubating yet that tells me she has probably one egg to go. I will make note of the date because we know Bluebirds incubate for 12-14 days and then should see babies.

  • Once I am certain she is incubating I do more monitoring from a distance. If you see the female exit the box and fly off that’s a perfect time to approach and take a look. Be gentle and quiet. I like a box that has a door that opens down as opposed to up. It is so much easier to monitor in a subtle way. I also take pictures to share with people.

Eggs laid before incubation.

Fledglings days after hatching.

Fledglings about a week after hatching.

  • Now the babies have hatched and I’ve noted the date because we know the babies will take about 14 days to develop and be ready to leave the box. This is known as the fledgling period.

  • I will monitor daily until by my calculations tell me there are just 2 or 3 days to go until they fledge. At this stage of their development the babies may be fearful enough to want to get out of the box if you open it. I monitor from a distance watching the parents as they make repeated trips with food to satisfy all those appetites.

  • Hopefully, the calculations are right and you may get a chance to see babies fledge. You will see more animated behavior from the parents as the first and second babies are about to come out for their first flight. Do not be alarmed if all the babies don’t fledge at the same time. It may take several hours for all to fledge.

For more information about Bluebirds and monitoring please visit the National Bluebird Society website. http://www.nabluebirdsociety.org/bluebirdfacts.htm


Basics of monitoring Bluebird and other birds nest boxes

Female & male bluebird building nest.

Female & male bluebird building nest.

Female Eastern Bluebird.


The Wood Thrush Shop encourages people to be a little more involved during the period of time a bluebird, chickadee, or some other native bird, is raising their young in a provided nest box. Certainly, these birds are capable of doing all the important work themselves, but by monitoring you will be treated to a very interesting and amazing process. You may even be able to help them should a problem arise, like an ant infestation.
What is monitoring? Monitoring a nest box may include regular observation from nearby, and periodically opening the box, just enough to take a peek to see what phase of the process the nesting birds are in. Monitoring for me means doing a little of both.

Early Monitoring

· Look for signs of interest from birds. Regular daily appearances? Are they bringing nest material to the box, going in, or just perching on it for periods of time?
· Do you see competition for the nest box among different birds? You may see some territorial bouts, or some courtship behavior.
· Just observe a little each day.

Let’s jump ahead and say a pair of bluebirds has indeed chosen your nest box. Congratulations! Now how do you monitor?

· You’ve seen considerable activity by a pair of bluebirds at the nest box. When the Bluebirds are not present open the box and take a good look. What kind of nest material is being used? Bluebirds will most often use pine straw or fine dry grass. A nest may take hours or longer than a week to complete.
· Now you will be looking for that first egg. Bluebirds will typically lay between 3-6 eggs. When the nest appears to be complete it is recommended you begin looking in the nest box in the afternoons or evenings. Why? Because Bluebirds and other songbirds tend to lay eggs during early morning hours. You wouldn’t want to disrupt egg laying. Not that a bluebird would abandon the nest site because of one disruption but repeatedly could be cause. They will lay one egg per day until complete.
· Only after the female has laid the last egg will she begin incubating. Let’s say on the 4th day of monitoring the box you see a fourth egg. I would recommend you do not look on the 5th day in case 4 is where she stopped and is already incubating. Now is the time that I usually refrain from looking in the box unless I have witnessed her leaving the box temporarily to get some food and to stretch. Take note of how many eggs there are and their color. Bluebirds usually lay blue eggs, but sometimes they are white. I continue to observe from a distance, or a walk by close enough to be able to see something that might be of concern.

Bluebirds usually lay four to six eggs. They can range anywhere from off white to light blue to this bright turquoise.

Bluebird nests mainly consist of dried grasses. Dried pine needles are seen often too.

When you are certain the last egg was laid on a particular day, or the next, mark on your calendar, or smart phone, “14 days until hatching”. The female will incubate between 12 and 14 days at which point the babies will begin to hatch. Again, afternoons will be a better time to open the box to monitor. With cool nights and mornings the female will still be sitting with the chicks keeping them warm.
The Fledgling Period
For the next 15 to 18 days the baby bluebirds will be going through tremendous change. Again mark on your calendar the approximate day they will fledge from the box. Just 15-18 days after hatching! Daily brief looks in the box is fine. You may choose to look every two or three days.

Just hatched Bluebirds.

Starting to grow feathers. 5-7 days in.

Starting to grow feathers. 5-7 days in.

Almost ready to fledge. 14-16 days in.

Almost ready to fledge. 14-16 days in.

· You will see naked baby birds with eyes close during the first days. Near the end of the first week they will increase in size and begin developing their first feathers.
· By the 9th or tenth day they will be feathered but the feathers continue developing. By this time the babies will have more than three quarters of their final body weight. You may be able to determine the sex of the babies based on color of wing feathers. Those of the male will be bright blue, while females a pale gray-blue.
· At around the 12th or 13th day the babies are quite active in the nest and you may see signs of heads poking out of the entrance hole getting a look at the world. It is at this time we recommend not opening the box to look at them.They may be developed enough to leave the box if frightened.
· Keep observing from nearby and look for increased visits from the adults feeding young.
· In another couple of days babies will be ready to leave the box. Usually it takes a couple of hours for all the babies to finally leave where they will remain in a loose group, staying hidden in trees while the adults continue to tend to their feeding needs.

Congratulations, you have successfully monitored your Bluebird box. Now pull out the used nest material and be prepared for the next pair of birds to come along to begin nesting.

Wood Thrush Shop Notes

Do you realize the first reported sightings of Ruby-throated hummingbirds are just a couple of weeks away? Usually by the last week of March a few hummingbirds will be seen in mid-TN while the bulk of them will make their way into and through TN between mid-April and mid- May.

But don’t rush to put out all your feeders just yet. We recommend one feeder with a small amount of nectar for early season migrants. Remember, don’t use the red stuff. At this time of year you are not likely to see much action at a feeder as lone males and females are making their journeys to breeding locations, which may be in your backyard or as far away as Canada.

For daily bird sightings reports of migrating birds you may want to subscribe to TN bird, or visit Tennessee Birding on Facebook.

Carolina Wren nests consist of dried leaves, grasses, and moss. They really pack it in, filling most nest boxes all the way up and around the hole.

Eastern Bluebird nests consist of mostly dried grasses, and or pine straw.

Photo from last year.

Has anyone seen eggs in a nest yet? I am keeping a close eye on a box in which Carolina wrens have completed a nest and a Bluebird box with a finished nest. This is no surprise as Carolina wrens are notable early nesters. I’m so glad they chose a nest box rather than my canoe this year. But I typically do not see a Bluebird nest this early.

A completed Bluebird nest at this time does not mean it’s a done deal. Over the years I have been disappointed to see Bluebirds working on nest building only to eventually decide on another location. They may complete a nest and not actually lay eggs until several weeks after.

So the word of the day for you Bluebird enthusiasts is PATIENCE. And if you see two different species (Chickadee, Bluebird for example) competing for a nest box let them work it out. It is always a good idea to have more than one choice of nest box a comfortable distance from one another to alleviate competition. What’s a comfortable distance? A general rule is 100’ apart or if closer out of sight of one another.

Keep an eye on your nest boxes and let us know if you are seeing active nests.

Protecting Bluebirds Nests from Raccoons and Rat Snakes

Raccoons and Rat snakes are formidable predators and can be dealt with in much the same way. Raccoons are intelligent and great climbers, and Rat snakes are supreme climbers. Not all of us presenting Bluebird boxes will encounter one of these predators but if you experience regular and on-going visits from Raccoons at your bird feeders it is likely they will eventually find a nest box full of eggs. We would encourage you to employ a Raccoon baffle on a pole to protect your Bluebird box. Raccoons are very much opportunistic. If you make it difficult to climb a pole there’s a good chance they will move along to easier opportunities. We carry baffles that will fit a metal pole up to 1 ¾” diameter, and wood posts up to 3 5/8” (todays 4x4). It should be noted a squirrel baffle may, or may not stop either one of these predators. But a squirrel baffle is better than no baffle at all.

Box placement has proven to be a factor, too. My 10 box Bluebird trail in a field has had no predation by Raccoons in many years of service. Boxes placed more in field and meadow situations tend to see less raccoon activity. Boxes placed adjacent to woodland and stream environments tend to see more. In this situation placing a nest box on a tree is not advised. This goes for rat snakes, too. A good raccoon baffle should stop both raccoons and rat snakes the vast majority of the time. For do it yourselfers you may want to check out the National Bluebird Society website for plans on PVC baffles and other critter stopping hardware and tips. Predator control pdf

And let us know if you are dealing with a persistent House Sparrow. We have an odd contraption that is a potential solution. More on that next week.

This Weeks Special

All Squirrel and Raccoon Baffles 20% Off

Through March 18th.