Eastern Bluebirds Nests and Eggs: All you Need to Know

This article provides comprehensive coverage of the eggs and nests of bluebirds, encompassing various relevant aspects. It delves into detailed descriptions of egg characteristics, the timing of egg laying, the process of incubation, and more. Furthermore, the article explores bluebird nesting requirements, including nest placement, along with other important aspects of bluebirds’ nesting biology.

bluebird nest and eggsPhoto: John Brandauer /Flickr/CC by 2.0

Among folks who keep bluebird houses (nest boxes), one commonly asked question is what to do with unhatched eggs when the rest have already hatched or what to do with unattended eggs in a nest.

These questions also apply to nests outside birdhouses. Naturally, many bird enthusiasts want to help when they perceive a problem.

This article goes through some basic information about bluebird eggs and nests to help you make informed decisions.

Where do Eastern Bluebirds nest?

Bluebirds are obligate cavity nesters, which means that they only build nests inside a cavity, a chamber, or a structure that resembles a sheltered chamber.

Cavity-nester: A bird that exclusively or nearly exclusively nests in natural or artificial cavities.

A cavity is defined as a chamber with an entrance that shelters the nest, eggs, and brood.

Cavities can be natural, such as those excavated by woodpeckers, formed by broken-off branches of trees, or artificial, such as birdhouses, also known as nesting boxes.

There are two types of cavity-nesting birds:

  • Primary Cavity Nesters are those that are capable of making their cavity. A typical example is woodpeckers and Flickers. Some birds, such as Titmice and Chickadees, can make their own cavities or expand existing holes in soft or rotten wood.
  • Secondary Cavity Nesters are those that are unable to make their cavities. They are secondary users of either natural cavities or those made by others. Bluebirds, and most cavity-nesting species, are secondary cavity nesters.

When nesting in natural cavities, Bluebirds use cavities excavated by woodpeckers 77% of the time.

When it comes to preference over artificial or natural cavities, Bluebirds have no particular preference. Field studies found that some pairs nested in a nest box and switched to a natural cavity, and vice versa, in a single nesting season.

On very rare occasions, Eastern Bluebirds have nested outside a cavity.

A literature review reveals that bluebirds, on rare occasions, have built a cup-shaped nest on a bank on the ground and in a fork formed by thick branches.

Allaire (1976) reported a nest on the ground on surface-mined lands in Kentucky. Sprunt (1946a) reports a bluebird nest on an oak limb in Clemson, South Carolina, and another in the longleaf pine (Pinus palustris) forests of Alabama.

Bluebirds rarely nest outside a cavity.

Bluebird nesting in a gutter. Photo: Deny Lammardo.

There have been reports of bluebirds nesting in gutters that appear to be enclosures. However, nesting on the ground or tree branches has not been reported in recent years.

A substantial percentage of Eastern Bluebirds nowadays nest in birdhouses. Plenty of nest boxes are available to nesting bluebirds, partly explaining why there are not many records of bluebirds nesting outside cavities.

Nowadays, more nesting sites are available, but cavities of any type are always in demand.

Bluebirds compete for nesting sites with other secondary cavity nesters such as chickadees, titmice, nuthatches, wrens, great crested flycatchers, tree swallows, European starlings, and House Sparrows.

When do Bluebirds build their nests?

As a rule, Bluebirds that stay in their territories year-round, such as those in mid-eastern and southern warmer states, initiate nest building earlier than those migrating to the northern and cold regions of the Bluebirds’ range.

Year-round residents begin nest building during February and March, the same period migratory Bluebirds are just arriving in the northern states.

In the states of Michigan and Minnesota, Bluebirds start building nests in March and late April.

The female alone builds the nest.

During the establishment of the territory and mating periods, the male performs a nest-building display. The male brings some nesting material to the nest to lure the female into the cavity or birdhouse.

However, his contribution to the building of the nest ends there.

For birds that mate for life, Bluebirds do not share the nesting activities equally. The female alone builds the nest in approximately 5.5 days.

The nest is an open cup. The base is composed of longer, thicker, and generally more coarse nesting material, while the cup is lined with delicate fibers mixed with pieces of bird feathers and mammal fur if available.

Some nesting territories have multiple cavities. Some pairs build a nest or the beginning of one in each cavity—however, the nesting pair use only one to lay the eggs and raise the young.

When does egg laying begin?

The female Bluebird begins laying eggs between 6 and 7 days after the nest is completed.

The overall timing of egg-laying throughout the Bluebird’s range reflects the timing of nest building. Egg-laying begins during February and March in the warmer southern states and March and April in the northern and colder states.

During April, most breeding Bluebirds are at least incubating eggs.

How many eggs does a female Eastern Bluebird lay?

Bluebirds typically lay 4 to 5 eggs, though they can have clutch sizes of up to 7 eggs in some cases. The female lays one egg every day.

On rare occasions, two females may lay eggs in the same nest. Both females incubate and feed the chicks.

Approximate length of the breeding season

Although variable across the Bluebirds range, the breeding season lasts 83 days on average or nearly three months.

When does the Eastern Bluebird initiate egg incubation?

female bluebird incubating eggs
Photo: Wendy /Flickr/CC by 2.0

Bluebirds typically start incubating the eggs on the day the female lays the last egg of the clutch. Less often, a female will start incubating the eggs a day before the last egg is laid.

The incubation time is shorter in warmer regions and slightly longer in northern and colder states.

What is the eastern bluebird egg color?

Typical bluebird eggs

The color of the Bluebird egg usually is blue. But rarely some females lay white eggs or pink eggs only.

Rare white bluebird eggs.

Egg color is not alternated within a single clutch. In other words, a female lays either all blue, all white, or all pink eggs in one clutch.

Incubation Period

The incubation period is variable within the Bluebird’s ranging between 11-19 days with an average of 13.5 days. Bluebirds in the warmer southern states have slightly shorter incubation periods than those in colder northern regions.

Do male and female eastern bluebirds incubate the eggs?

No, only the female incubates the eggs. The male does not participate in the incubation of the eggs.

The male protects the territory and brings food to the female while she is incubating the eggs.

The female takes breaks to feed and poop in the morning hours and throughout the day.

During these breaks, both the male and female forage near the nest and keep an eye open for predators approaching the nest.

In what instances do eastern bluebirds abandon their eggs?

In most cases, bluebirds abandon their eggs for compelling reasons. Based on field observations, a mated Bluebird pair is more likely to abandon its eggs if either the male or the female has died. Lack of food and extreme weather events are also contributing factors.

Extreme weather events and lack of food are related. Generally, cold weather suppresses insect population growth and makes them less mobile and harder to detect by bluebirds. Therefore, bluebirds must spend more time looking for food, ignoring the eggs, or even temporarily moving to areas where food can be found.

Repeated harassment by predators is another reason. There may be constant attempts by predators to get inside the next box. Despite being unsuccessful, such harassment may prevent the female from incubating the eggs. Nesting pairs may not find it worthwhile to continue since eggs and nestlings may eventually be taken by predators and move to another nesting site.

Another less frequent reason is that the parents may realize that the eggs are not viable after incubating longer than usual. They can abandon the eggs and move to another nest site or build a nest on top of the eggs and restart breeding.

Nest abandonment depends on when one of the pair is lost

Because male and female Bluebirds have specific roles during the breeding season, the timing of losing one member of the pair may result in different outcomes.

Scenarios include:

  • If the female is lost during the nest building, egg-laying, and incubation periods, the breeding attempt fails because the male does not do any of these activities.
  • If the male is lost during egg-laying through incubation, field observations indicate that the female will likely abandon the nesting attempt.
  • If the female is lost when the brood is very young, the nesting attempt fails because the male does not brood the young, and they will die from hypothermia.
  • If the male dies when the brood is very young, the female could raise the young.
  • If either the male or female dies when the chicks are still in the nest but have feathers to thermo-regulate their temperature, the remaining parent can raise the young through fledging.

While any of these scenarios can result in nest abandonment, a likely outcome is that another bird replaces the missing member of the pair. The new replacement may help feed the young if these are old enough or ready to fledge. Conversely,  the new replacement will likely not show interest in eggs or very young nestlings.

It appears my Bluebirds have abandoned the nest!

Sometimes long female absences from the nest occur when the temperature is warm or hot. The female stays outside and returns when she senses the eggs need to be incubated.

If the female has not been in or around the nest for two consecutive days, she may have died.

Another female is likely to replace the missing female. This replacement may take weeks or can occur within hours if females nearby are available.

The new female and male will proceed to start a new nesting attempt if it is early enough in the season to start one.

bluebird eggs and nest in nesting box
Photo: Jane Kirkland /Flickr/CC by 2.0

How long will the female Eastern Bluebird sit on unhatched eggs?

The female Bluebird will sit on her eggs until the eggs hatch in 13 to 14 days.

If some of the eggs do not hatch within 72 hours or three days after all other chicks have hatched, it means something went wrong with those eggs, and failed to hatch.

Studies on Bluebird nests indicate that about 83% of eggs regularly hatch. Typically, 17% of eggs never hatch.

If, for instance, all eggs fail to hatch in 13 to 14 days, the female will continue incubating the eggs for a few more days until she realizes the clutch has failed.

The pair then builds a new nest on top of the failed clutch and starts a new breeding attempt.

When only one or two eggs do not hatch, but the rest do, the parents remove the unhatched eggs or are unintentionally crushed by the growing chicks. The female then proceeds to remove the shells.

How do you know if an unhatched egg is still alive?

A live egg releases CO2 and intakes oxygen through microscopic pores on the surface of the shell. If this exchange of gases occurs, the egg should look smooth and shiny.

If the egg is dead, the surface is dull. If the egg has been dead for some time, it should feel weightless.

If the egg has recently died, a close sniff should reveal a foul smell.

Dead eggs of other birds ooze a light brown substance. If the Bluebird egg oozes a substance of any color, they are dead.

Use the candling method.

Candling is a standard method used to detect if chicken eggs are still alive.

Gently take the egg to a dark room and hold the egg before a light or flashlight. When light penetrates the eggshell, it shows veins running through it or a red content that indicates the egg is still alive.

Should I remove unhatched eggs from a Bluebird nest?

You should never remove unhatched eggs unless you are sure the nest has been abandoned or the eggs have failed to hatch (read above).

Why do some Bluebird eggs fail to hatch?

There are many possible reasons. Often we never know why an egg fails to hatch.

Some of the more probable reasons include too hot or too cold temperatures, pesticide exposure, genetic malformations, and bacterial infections.

Cold weather is a big problem for eggs and very young birds.

In general, bacteria may have found their way into the egg during egg formation inside the female. Bacteria continue to grow after the egg has been laid and eventually kill the egg.

Sometimes females lay eggs in another pair’s nest.

Bluebird studies where eggs were manipulated and genetically studied found that sometimes other females lay fertile eggs in another pair’s nest.

This is called conspecific brood parasitism, which occurs when a female uses or relies on another pair to raise their brood.

This may happen when a female with fertile eggs loses its nest to predation when laying eggs. She must deposit her egg somewhere rather than lose them.

Female Bluebirds guard their nests to prevent other females from laying eggs in their nests. Despite that, other females manage to sneak into other nests and lay eggs.

Bluebird eggs have been found in nests of other cavity-nesting birds such as Carolina Wrens, Chickadees, and even in nesting boxes of House Sparrows.

Different bird species may also lay eggs in a Eastern Bluebird nest

Although this is not common, eggs of European starlings, Brown-headed Cowbirds, and House Sparrows have been found in Eastern Bluebirds’ nests.

The Brown-headed Cowbird is a known brood parasite. But parasitism by Cowbirds on Bluebird nests is rare when the cavity entrance is too small to allow a female cowbird easy access.

The same holds for nesting boxes. Nests with an entrance hole of 5.4 cm (2.1 inches) in diameter and larger were parasitized by cowbirds more often than entrances with a smaller diameter.

How does the female Eastern Bluebird react to the presence of eggs from other bird species?

Most female Bluebirds that notice eggs from other birds will cover the entire clutch with nesting material, build a new nest, and start another nesting attempt.

What are the main Bluebird egg predators?

Bluebird predators that can damage the eggs include House Sparrows, House Wrens, and woodpeckers.

Predators that can kill young birds include fire ants.

Predators that can eat eggs, young birds, and adults include cats, raccoons, and snakes.

References:

  • Allaire, P. N. (1976). Nesting adaptations of bluebirds on surface-mined lands. Kentucky Warbler 52:70-72.
  • Eastern Bluebird, Life History. All About Birds. The Cornell Lab of Ornithology.
  • Gill, Frank (1995). Ornithology. New York: W.H. Freeman.
  • Sialis Online. Bluebirds.
  • Sprunt, A. (1946a). Unusual nesting of two birds in South Carolina. Auk 63:94-95.
  • The Birds of the World Online. Eastern Bluebird (Sialia sialis).  Cornell Lab of Ornithology, Ithaca, New York.

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61 thoughts on “Eastern Bluebirds Nests and Eggs: All you Need to Know”

  1. I live in north Florida and my bluebirds laid their third brood in early August. It became apparent that the female was sitting on sterile eggs after 25 days. I then left for three weeks and when I returned she was still sitting. There are three eggs and I will candle them to see if they are viable. Something may have occured in my absence. However, the male is no longer around and I believe she is still sitting on nonviable eggs. Viable or not, should I remove the eggs? She is an old thing who knows me and I don’t want to freak her out, nor do I want her to sit forever on these eggs!

    1. Hi Kathy,

      I would not remove the eggs as the pair, during your absence, might have laid a new clutch over the first non-viable one. Bluebird can build a new nest over the existing one to start a new breeding attempt. There is no rush to do anything at this point as the breeding season is practically over. I would would let things run their course. Once they/she stops incubating then it would be safe to remove everything and clean up the nesting box for the next season.

      Good luck,
      Al.

  2. I live in Maine and this year we had a very cold, rainy summer. This fall when I went to clean out my nesting boxes, I found a bluebird nest with nine unhatched eggs. What could have caused the eggs not to hatch this year?

    1. Hi Deb,

      Many causes. Perhaps a late start of second nesting attempt?? or one of the parents died or disappeared. I would clean up the nest and get it ready for the next nesting season.

      Good luck.
      Al.

  3. I put my first Bluebird nesting box up about two weeks ago. No activity yet. I am on the Eastern shore of Maryland. I installed the box per directions and also spoke with local Blue bird enthusiasts. I believe I have done everything correctly. We have had extremely high winds this week. I notice very slight shaking of box when it gusts. Is this going to be a problem?

    1. Hello Valerie,

      Slight shaking of the box should no be a problem. But, if it is shaking, it may mean that the pole and box are not sturdy enough??? Please, make sure that the nesting box is secured and equally important, that it has a snake guard.

      Good luck,
      Al

  4. I’ve had two bluebird boxes with new nests in them for 3 weeks and no eggs. I’ve seen a male now and then but no females. My question is, should I remove the nests seeing as there are no eggs in either box?
    I’ve had bb boxes for many years and really can’t remember this happening in two different nesting boxes.
    Any information would be greatly appreciated and thank you.

    1. Hello Polly,

      Please, do no remove the nest. It is early in the season and these may be returning males that arrive early or resident males that start early. Females usually come back later (I don’t know where you are located).

      Give them some time and you are likely to see females showing up and pair up with those males.

      Good luck,
      Al.

  5. This is my first attempt with bluebirds. I put a new house up on a T-pole and watched as a pair scoped out the box and eventually built a nest. I’m in northeastern Oklahoma. Mom laid 5 beautiful eggs and was in the process of incubating them. We had a storm last night and this morning the hole to the box was crammed with nesting material. A lot of material was also on the ground. After opening the box I can see 3 of the 5 eggs are gone. Perhaps a raccoon or squirrel was the culprit? Is there any chance mom will try to incubate the other two eggs? Have I lost them for the season? It’s March 25, 2024. Thank you so much.

    1. Hello Tracie,

      The missing eggs may have been damage by the shaking caused by the storm, to judge by the fact the nesting material was in disarray.
      The parents will continue incubating the remaining eggs.

      I am not sure a racoon can reach the eggs if the box is tall/deep enough. Squirrels are diurnal and are usually repelled by the parents.
      It is always a good idea to use a baffle to keep predators from climbing the pole and reach the nesting box.

      I hope all works well.

      Al.

  6. This morning we discovered 6 pink eggs on the ground, underneath a tea olive shrub of ours. We live in NC. There’s nothing that looks like a nest that they are in – just in the mulch & leaves present under the tree. I find this very odd. We have seen the bluebird pair around the house. I doubt that these will survive raccoons, possums & snakes – we live next to woods. Should we try and move them up into the shrub.

    1. Alfredo Begazo

      Hello Kathy,

      That is odd. I can only think of a nest of a tit mouse, or a chickadee (by the color of the eggs) that was raided by another bird. The attacking bird took the eggs out and may want to use that nest. The reason you don’t see a (typical) nest is perhaps because the eggs came from a cavity above the spot the eggs were found.

      Moving the eggs would not help, they are likely cracked and damaged. What would help is perhaps setting up additional nesting boxes.
      Good luck,

      Al

  7. Keith Wilkins

    We live in the Florida Panhandle. I built a blue bird box several years ago. We had one viable hatching a couple years ago, then nothing last year. A new nest and eggs appeared this year but we haven’t seen the parents in weeks. It is on a privacy fence and we fear it was susceptible to neighborhood cats. I was going to move the box to a safer location but now with eggs not sure what to do? Go ahead and move the box, wait longer for the parents to show up, check the eggs for viability…?

    Thanks, this is a great site,

    Keith

    1. Hello Keith,

      If it has been several weeks since you last saw the parents, it appears that something happened. One of the parents may have been taken by a predator or the parents decided that, for some reason, it is risky continue nesting there and decided to move on; this is speculation and we may never know the real reason for the birds to abandon the nest and eggs.

      To your question, at this point it is safe to move the nesting box to safer place. Clean out the content and relocate the nesting box.

      It is very important to set up a predator-proof nesting box. There is plenty of information on the internet about making a bluebird nesting box predator-proof.

      Be mindful of the new location for the nesting box “near your house”. If the new location is close to trees, houses, or other structures, bluebirds may not like that and ignore it.

      Good luck,
      Al.

  8. I had a nest in a box with 6 eggs a week ago. A couple days ago I noticed some nesting material out side the box. Today I checked inside and also it’s the whole nest and the eggs are gone! What predator would remove the nesting material? It was a pretty big nest

    1. Hello Kyna,

      Interesting. A predator interested in the eggs and chicks would have left the nest there. I can think of a competing bird interested in the nest site; perhaps House Sparrows??
      Monitor who is visiting the nest box now to, perhaps, have an idea about the possible culprit.

      Keep us posted,
      Al.

  9. Hello. In NC. I built a birdhouse some twenty years ago and put it up, never paid close attention but did notice that birds would be in it every year. Well it started falling apart and I fixed it this year. Two days put up and it has a male and female blue bird. Well it’s full of nesting material. My question is do they stay in birdhouse before eggs are laid or only after. I’m new at this.

    1. Alfredo Begazo

      Hello Keith,

      The female stays in the nest only after finishing laying her complete clutch. During egg laying, she may spend more time in the nest.

      Prior to the initiation of egg laying they first build the nest but generally do not stay in it consistently.

      Al.

  10. I live in a rural county outside of Richmond, Va. There was a bird box on a large oak tree that looks pretty beat up. Ive left it alone for 13 years. Today I noticed the box on the ground. When I checked it out there were baby beaks in sight. This box has no plexiglass (all wood). I dont know if abandoned by parents but I put it back up where it was located. Should I try and get mealworms to feed or leave alone. Its located in a spot where I cannot easily view. Suggestions?

    1. Alfredo Begazo

      Hello Chris,

      If you put the box back up, that should be enough. Chicks will beg for food and that will let the parents know that they need to feed them. No need to supplement with mealworms, the parents can find plenty of bugs.

      I hope the chicks fledge the nest safely,

      Al.

  11. Patricia Owen

    We have been monitoring an Eastern bluebird couple through the entire nesting process. There were originally 4 eggs in the nest but we saw evidence that one was broken.

    On day 11 after hatching, we saw 3 babies in the nest. Then one of the babies fledged on day 18. He basically flopped to the ground and hopped around while the male parent started pecking him. We assumed he was trying to get the baby to fly. We saw the baby in our yard the next day but have no idea if he survived or not.

    We waited several days for the others to fledge before checking and then found 2 fully formed dead babies. We noticed that the parents stopped feedings around day 17 but thought that was a deliberate attempt to have the babies fledge.

    The parents seem to be starting over in the new nest box that we installed but this beautiful experience has turned into a nightmare and we are wondering what went wrong.

    1. Hello Patricia,

      That is an unusual situation. The fact that one of the babies left the nest so prematurely may suggest that something was bothering them inside. One possibility is that the nest experienced an extreme parasite infestation??? What killed the other two chicks is also a puzzle. Extremely cold weather can kill baby bluebirds in the nest; house sparrows might have gotten inside the nesting box??? It is hard to tell what might have happened.

      It is a good idea to clean up the bird house after the chicks have left. The new users will build a new nest.

      Good luck,
      Al.

  12. Hi, this is my first spring in Tennessee, after much struggle with a house wren’s dummy nest, a pair of bluebirds have finally settled in the nesting box in front of my house. Following a neighbor’s suggestion, I got dried meal worms, however, I also read somewhere the baby birds may not get enough liquid if the parents feed them too much that.
    Will a bowl of fresh water near the box help the situation?
    Thanks!

    1. Hello Shawn,

      I would think that the parents would naturally mix dry mealworms with freshly caught insects. However, a source of water would not hurt and would help other birds too.

      Good Luck,
      Al

  13. Terry Goodwill

    I have bluebirds every year. They have already had a very successful clutch that have fledged. They usually have two clutches every year. Is it best to clean out the nest after the first batch, or leave it for the next batch of egg? Thank you.

    1. Alfredo Begazo

      Hello Terry,

      In natural conditions, bluebirds will nest over the old nest. However, this practice may result in a high parasite load for the second brood. It is recommended to clean up the nest. It takes the parents about a week to build a new nest and this time it will be a fresh nest without a parasite build up from the old nest.

      Al.

  14. Elisabeth Infield

    Hi — I have (had?) bluebirds nesting in a box (it’s early May in Massachusetts). I haven’t seen the adults in a week or so. I’d like to check on them but worry that taking a peek will upset the parents. Is it ok to open a box that may have chicks?

    Also I haven’t been filling my birdfeeders, as I didn’t want to attract competitive birds to the yard. Is this a real concern or can I fill the birdfeeder for the finches and woodpeckers?

    Thanks for any advice!

    1. Alfredo Begazo

      Hello Elizabeth,

      Yes, it is fine to open up the nesting box and see what is happening inside. The parents will not mind and return to do their normal activities.

      I don’t see any problem with filling up your feeders. Seed eating birds do not compete with insect eating birds like bluebirds. I would not expect other birds visiting your feeders be aggressive to the bluebirds and their nest.

      Good luck.
      Al.

  15. Katherine Yenzer

    I live in the Florida Panhandle. My husband put up a nesting ox in our backyard. I asked him to move it to the front yard but before he got a chance a pair of blue birds started nesting. The problem is we have two dogs that like to hang out in the backyard. They cannot reach the nest but I worry about when the babies start to try and fly. Should we try and move the box or let it be? Also the male likes to fly at our kitchen window. I think he is flying at his reflection. shout I put tape on the wind? I am scared he will hurt himself.

    1. Hello Katherine,

      Please, do not move the box to the front yard. The parents would not recognize it as their nest and the eggs would be lost.

      Regarding the dogs in the yard, typically, the chicks fly to a nearby bush or tree after leaving the nest. However, some leave the nest prematurely and land on the ground; this could be a problem.

      Chicks take from 17 to 21 days to leave the nest after hatching. You may want to monitor the nest starting on day 16 after hatching. I would keep the dogs in the house during the days the nestlings are likely to leave the nest.

      I hope all goes well.
      Al.

      1. I live in northeast Georgia and have had 2 nice plastic commercial bluebird houses for about 10 years. Each is mounted to a metal rod pole and the poles are at opposite ends of a long hedge that I keep trimmed about 4 1/2 ft high. I have never had bluebirds until this year. I first noticed the male and soon a female showed up at one of the houses. They were around several days and I could see the female’s head sticking out occasionally. Then they were gone and I saw them no more. I was worried because they seemed to leave so soon. I didn’t check the house for another couple weeks because I didn’t want to disturb anything, but I actually didn’t expect to find a nest. Today I opened the door to find a nice clean nest inside but no signs there had ever been eggs or babies. If the eggs had hatched shouldn’t I, at some point, have seen a fledgling outside the nest or at least feathers or pieces of eggs remaining when I looked inside today? I’m so disappointed. What could be the explanation? Should I leave the nest and hope another pair shows up?

        1. Alfredo Begazo

          Hi Mike,

          It is hard to pinpoint a reason why they left, but it is not surprising; many birds do this or even build multiple nests and then decide for one. If I were to guess from your description, the bluebirds might have seen some snake, cats, or other predator that made them decide that spot and setting is not a safe-enough to continue putting an effort to raise a brood. Sure, there may be other reasons.

          Please, consider installing a predator baffle high enough from the hedge so that snakes cannot reach nesting box.

          Good luck,

          Al.

  16. I live in Fort Worth, TX. There was a BB house concreted in the ground when I moved in. At the time, I didn’t know it was a BB nesting house until about 2 weeks ago when I saw my first BB couple pitching camp there. I am not familiar with birds other than keeping four bird feeders in the yard, and they are always active, but I had never seen a BB. Mom has been incubating, and Dad is getting food and always watching the perimeter. Yesterday morning, I looked out to see what the two were doing, and noticed a squirrel was eating an egg, I ran out and saw the squirrel chewed a bigger opening to get what it wanted. Both parents continued to stay and guard the nest, so I hope the predator didn’t take all the eggs. I then began researching, ran to Home Depot, and bought metal stove pipe and bird spikes and put them around the wooden 4X4″ square pole and topped with spikes above the metal and on top and around the other exposed pole areas because squirrels have plenty of jumping places around this house. I didn’t do any drilling into the pole; instead, I used large zip ties because I didn’t want to drill or hammer on the wood and scare the parents. They stayed around for a few hours after I completed it, but by mid-afternoon, I didn’t see them anywhere. I stayed up all night last night watching from my bedroom window to see if they returned so Mom could continue her incubation. And to see if my predator deterrent worked for any nighttime prowlers. No predators, but also no parents. I’ve been heartbroken and do not know if I need to go peek in and see if any eggs are left, and more importantly, will the parents return? If so, should I not look to see if there are any more eggs? How long would the parents stay gone until I know if they aren’t ever returning?

    Signed, Michelle, a heartbroken first-time landlord

    1. Hello Michelle,

      Something similar happened to me with my woodpecker house, my daughter saw the squirrel getting out of the box.

      It was a great idea putting a predator guard. Not only bluebirds but all birds move on from nests that fail, particularly if they witness the predator causing the damage. At the same time, nest failures happen all the time.

      It is likely that the pair will not return this year. Another fresh bluebird pair may discover the bird house and use it this year if the original pair is no longer holding the area as a nesting territory.

      Go ahead and clean up the nest make sure the predator guard is in good wording order. If no other pair uses it this year, the next year is likely to be used.

      Good luck,
      Al

  17. Hi!

    Last week we had a brood of five baby bluebirds fledge. One fledged about three days before the other four. It’s been about five days since the last one left. We haven’t seen any of the fledglings since that first one, but we’ve seen adults hanging around the general area.

    This morning we’ve been seeing new nest building activity at the nest box. While it’s obviously impossible to know for sure, what do you think the likelihood is that this is a new couple rather than the original pair starting over? Five days seems too short of a period for the last ones to be ready to be on their own.

    Thanks!

    Natalie

    1. Alfredo Begazo

      Hello Natalie,

      Yes, that is too soon. Adult continue feeding the babies for two weeks or longer after leaving the nest. However, if there is plenty of food for just one parent (the male) to continue feeding the young while she starts a new brood, it could actually be the same pair. Hard to tell.

      Are they getting supplemental feeding (bird feeder)?

      Al.

      1. Hi Al!

        Yep, they have been visiting our bird feeder. It turns out that it was a second pair. We saw 3 babies hanging out with their parents for a little while. One got hit by a car last week. =(

        The new pair seem to be working on a batch of their own. Momma was in the box today. =) Fingers crossed that this batch will flourish!

        On a fun side note… Downy woodpeckers have decided to eat from our hummingbird feeder today. That’s one I’ve never seen before!

        Thanks for your response!

        Natalie

  18. I am in East Texas. I had a pair of Eastern Bluebird build a nest in a small decorative ceramic birdhouse handing from a shepherds hook. The 4th and final egg was laid 5/15/24. I’ve monitored the birdhouse by camera since 5/16. While my main concern was that these eggs/babies were going to get too hot in the Texas heat, we have had some really horrific storms. Yesterday morning during a really bad storm, a limb broke and knocked the birdhouse off the shepherds hook. I ran out during the storm and picked up the house, the momma flew out. I placed it securely, on a ramp right beside the shepherds hook, until the storm was over and rehung on the shepherds hook. I noticed the female still sitting on the nest after I rehung. Then every time I looked last night, I didn’t see her. Today I checked and there is only one egg left in the birdhouse. Do they move their eggs?

    1. Hello Elyne,

      No, bluebirds are unable to move their eggs from nest to nest. Missing eggs is usually due to predation by snakes or other predators. House sparrows and even starlings are known to puncture and take eggs out of bluebird nest boxes. Unless one witness the action, it is difficult to know the real cause of the egg disappearance.

      I hope the one egg left hatches successfully.

      Al.

  19. Michela Hirnak

    I monitor several bird boxes in Eastern MA, and one day 5 eggs were missing from a fully formed nest — no sign of broken egg shells anywhere, and the nest was not disturbed. A few weeks later a new clutch of 5 eggs are in place, so I’m hopeful. Any idea what happened to the first clutch, and do you think it’s the same pair who started the 2nd? The attempts were only ~ 2 weeks apart.

    1. Alfredo Begazo

      Hello Michela,

      Snake predation is the most likely cause of the eggs disappearance. Typically, snakes take the eggs or chicks and leave the nest intact. Please, consider using a predator baffle to prevent snakes and other predators from reaching the nesting box.

      Yes, it is quite likely that the second brood was initiated by the same pair.

      Good luck,

      Al.

  20. Adrienne Lloyd

    Bluebirds already hatched and fledged a clutch of chicks this spring and after I cleaned the box out, they built a new nest and laid 3 eggs. Then the parents disappeared for almost 2 weeks. My yard is small and I am out there most of the day every day so I would have seen them coming and going. I assumed the nest was abandoned for whatever reason. Today I looked and the 3 eggs were still there. They looked fine but had to be at least 2 weeks old. I candled them and they just have a yolk and no veins or fertilization spot. So I removed the nest and eggs. Within 30 minutes the bluebirds came back and began their usual dance of in and out of the box that they do before they build a nest. Were they just waiting for me to clean the nest out for them? Could the eggs I took out still somehow be viable? Should I put them back? A lot of people on my birding Facebook group were yelling at me, saying I did the wrong (and apparently terrible) thing. I’m new to bluebirds and nests and I need advice!!!

    1. Hi Adriene,

      Based on the description of the events you did right. Two weeks without the parents around is a long time. The female typically begins incubating, continuously, after laying the last egg. While unincubated eggs remain viable for a long time, it is likely that something happened to the pair that laid the eggs.

      From a breeding productivity stand point, whether it is the same or a different pair, the nesting box is now being used and a new set of young bluebirds will be produced out that box. We’ll never know what would have happened if you left the eggs there and other bluebirds would not use the box because it appeared occupied. Bluebirds lose clutches and renest all the time.

      Al.

  21. Matthew Moment

    I have had a pair of bluebirds at my nesting box for the past 25 days. 14 days ago, I peeked in the box and saw one egg. Both male and female seem to be actively protecting the nest and feeding. Should I be looking inside the box? I’m afraid to spook them but I’m also curious to know if there are more eggs or if any of hatched. As I said, I just don’t want to scare them off at this point.

    1. Hi Matthew,

      Bluebirds are tolerant of people opening up nesting boxes to check the content. However, this should be done early in nests that have eggs or young chicks. Given the number of days, chicks may be old enough to be afraid of someone opening up the box. This type of disturbance can cause premature fledging where chicks fall on the ground unable to maintain sustained flight. This puts the chicks in an increased risk of predation by ground predators.

      It may be a good idea to leave them alone this time.

      Al.

  22. We have a bluebird couple around all the time. They have built a nest in our box but no eggs. We see them go into the box several times each say and see them sitting on limbs close to the box. It is now the first of June and no eggs.
    What is going on with this pair?

    1. Alfredo Begazo

      Hello Iris,

      They are taking their time and delaying egg laying for some reason. It is often difficult to tell why some take so little time to begin laying eggs while others take longer. Some pair leave the already built nest and move on.

      I hope they lay eggs soon. It is fun to watch them through the nesting process.

      Al.

  23. Renee Chambard

    Bluebirds are nesting in our nesting box and there have been 4 eggs in the nest for about two weeks. The pair can be seen going in and out of the box during the day so we know the nest hasn’t been abandoned but the female doesn’t appear to be sitting on the eggs. Is this typical? We find this odd since it’s been so long since the fourth egg appeared.

    1. Alfredo Begazo

      Hello Renee,

      After two weeks, it is about time for the eggs to hatch. If you see both parents going in and out it looks like they are feeding young. Only the female incubates the eggs, but you see both going in and out. Soon you will see the babies peeking out the nest entrance.

      Good luck,
      Al.

  24. Thom Harris

    We got back to Northern Michigan end of April this year,
    Built a bluebirds house with grandson, on a conduit pipe with guard 6.5 ft off the ground. We placed the house according to guidelines. House up on May 1.
    Male & Female arrived one week later, nest built, checked box 2 weeks ago 3 eggs.
    We had a cold spell last weekend (40s) for 4-5 days.
    Haven’t seen mom for several days, even before cold spell. Haven’t seen Dad this week.
    Checked box yesterday 3dead hatchlings very small guessing died during cold weather???
    Will another pair nest this late in the year?
    Notice redwing blackbirds are hangin around. Could they spook the bluebirds?
    Sorry for the lengthy message but first time and are really blessed watching bluebirds and make our place their home.

    1. Hello Thomas Harris,

      Cold spells as are a frequent cause of nestling mortality. Please, remove the nest and the dead chicks. It is late in the season, but they may start a new brood.

      Regarding the red-winged black birds around, they are not a threat to bluebirds nor compete for nest sites. Blackbirds nest in open-cup nests built in wetland vegetation.

      I hope your bluebirds start another brood.

      Al.

  25. Beth Baisley

    We have three bluebird houses in our yard. One is a new one with the camera built in. Mom and Dad have used both of the old house for their broods. We have set up the new one right near the old ones. Mom is starting to build her third nest of the season. We were really hoping to get her to use the new one so we can monitor it more with the camera instead of opening it and bothering her. She is just making her nest now. Would she get upset if we moved the nest into the new house?

    1. Hello Beth,

      Iam not quite sure what the idea is. Do you mean replacing the box where she is building the third nest of the season with the box that has a camera? I would not recommend doing that. She may not recognize the new box and nest and abandon the breeding attempt. Your best bet is waiting until the next year placing the box with the camera where one of the old boxes (the ones they used this year) are. They are likely to choose the box with the camera thinking that it is the box they used the year before.

      I hope it works out.
      Al.

  26. Suzanne M Cook

    I need help. We have hundred of blue birds here on our farm in Michigan, but a pair made a nest in my tractor exhaust along with 3 eggs. It had only been sitting for 5 DAYS. I started it up and shot everyone out the top stack. One eggs lost but two still in the nest which I grabbed before it tumbled down.

    I have an incubator, but I’m already hatching 4 wild turkeys whose mother was chopped by my hay cutter this year and frankly I am swamped with work.

    On a hunch, I carved out a plastic container and set the nest inside and put it near the tractor stack hoping the mom will come back. While my 11 year old boy is pining at the idea of raising blue birds, I’m not sure how migration will go later this fall . . .

    What should I do? (It’s been in the 80’s plus humid so I’d say they are ok for a day or two..)

    1. Hello Suzanne,

      It is unlikely that the mother will recognize the nest at its new location. It was an accident. Birds lose their eggs all the time. One thing to do is covering the tractor’s exhaust (when not in use) so that this does not happen again. Also, you can set up nesting boxes for the next breeding season.

      Good luck.
      Al.

  27. I live in southern Georgia and we are having an uncommon heat wave with temps between 90-100. Some eastern bluebirds laid a 4 egg clutch and on the 13th day 1 baby hatched and is thriving. However, 3 eggs did not hatch on this the 19th day. I see that they still appear to be a bit shiny and not completely dull, but it’s more than the 4 days spoken of since the 1st hatch. This particular birdhouse has a very small latched door in lower section but nest is built over it, so it makes it almost impossible to get in there to remove the unhatched eggs. I only know the rest via a cam in the upper part of the house. Will the baby be ok with the unhatched eggs? I guess if I wasn’t watching I wouldn’t know anyway and nature would take it’s course….

    1. Hello Debbie,

      Yes, the baby bluebird will be fine. As it grows bigger, it will sit over the eggs which, will become brittle over time. The eggs break and settle on the bottom of the nest and will not be an issue.

      Al.

  28. Blue Bird box with bottom predator shield and Sparrow Spooker installed after second brood of the season. The first brood produced five babies of which after leaving the box, I never saw them again.

    Cleaned box and two weeks after the fledglings left, the Blue Birds began making a new nest. Four eggs produced and 14 days later, two were on the ground in front of the box. Egg yolk present with no sign of babies in the eggs. A day later, the other two eggs on the ground broken, again with no evidence that the eggs contained babies. Mother Blue Bird sat on the four eggs for 14 days. The nest is perfect and we have not observed any other birds entering or exiting the box. I removed the Sparrow Spooker until a new egg is observed.

    The parents appeared to be confused both days of what happened, looking inside and standing on the box. The male has been enticing the female to lay more eggs in the box by adding a few pieces of grass inside the box on the existing nest. Both continue to enter and exit the box, as well as standing on top of the box.

    Any ideas what happened? One theory that I had was the Blue Blue birds punctured the eggs and removed them when they realized they were not growing a baby in the eggs?

    Thank you! Doug

    1. Hello Doug,

      Your theory makes a lot of sense particularly at this point in the season. They would want to get another brood out and recognize that there is not much time left and want to speed up things.

      However, bluebirds would continue incubating their eggs well beyond the time they were supposed to hatch. While your theory has some challenges, the fact that the eggs had no embryo at day 14 of incubation supports the fact that the parents somehow realized that the clutch was not viable.

      Very interesting, perhaps someone else here knows more about this??
      Al.

  29. Wonderful creatures, these Eastern Bluebirds.

    About three weeks ago in a nest box she laid 4 blue eggs. Checking it today, there is one blue and four white eggs. I’m not concerned about the “how”, or “why”. Nature will do what it will do, and I’ll take steps to protect them in the man-made box. Just wanted to share the info with other enthusiasts. Wish there was a place here to share my photo.

    1. Hello Hap,

      That is so unusual. Tree swallows, which often compete with bluebirds for the same nesting boxes, lay pure-white eggs. But what happened to the other three blue eggs?

      Perhaps someone here can chime in on this.

      Al.

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