Do Blue Birds Mate for Life?
Birds True Love

Wondering if the pair of bluebirds you saw earlier will remain monogamous? They almost always do, but you'll be amazed to read about some exceptions!

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David A. Swanson

July 25, 2021

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What’s This Post About?

Bluebirds are said to be messengers that come to bring happiness and love. They are thought to represent joy, excellent health, and fortune. If you’ve been seeing bluebirds a lot lately or seeing them in your dreams, it’s a sign that something nice is coming your way.

When most people see a pair of bluebirds, they imagine them mating for life and rearing their children together. Several observers like to point to these birds as proof that monogamy occurs organically in creatures other than human beings.

The majority of the bluebirds do mate for life. The others that don’t have reasons justifying it. There are many underlying causes like nesting failure and the death of a partner that can change the bird’s mating status. Bluebirds’ relationships are unique, even if they aren’t always faithful to their lovers.


Do Bluebirds Mate for Life?

Mating for life indicates that the bonded couple will continue to pair year after year and actively contribute to the upbringing of their kids.

Research on Eastern Bluebirds suggests that around 95% of the time, just one male and one female are involved in nesting. During the mating season, bluebirds establish pairs. They are “mating pairs,” which means that a lone male and female constitute the fundamental social unit in nesting territory.

Bluebirds are monogamous passerines who generally form long-term relationships. They have, however, been observed to participate in copulations outside of their established bond on occasions. This means mating outside their monogamous relationship.


It is more probable that the female mates with an older male invader in some situations of extra-pair copulation.

How Do Bluebirds Choose Their Partners?


Before they commit to mating together, bluebirds must actively pick each other as spouses. The male bluebird is the one who must try to win over the female bluebird. He attracts the females through different body movements and songs directing towards the nesting site he has chosen.

Trying to win over a female is easily accomplished by demonstrating that the male can be a valuable contributor.

The male bluebird does this by accumulating nesting materials into an ideal breeding chamber for the female. The female chooses the site and the material more so than the male bluebird himself.


A male can sing up to 1,000 songs every hour when seeking to attract a partner.

When Do Bluebirds Form Pairs?


Pair creation occurs at different times, depending on geography. Around the warmer southern states, pairs begin to form in mid-January. On the other hand, birds in the colder northern hemisphere begin to form pairs during February and March.

According to observational data, birds typically arrive at the mating grounds as a couple. This suggests that bluebirds appear to start forming partnerships when still in their journey towards the north when they gather in flocks.

Moreover, migrating Bluebirds that still haven’t found a partner to make a pair with tend to locate a partner and create a nesting region within a week of landing on the nesting site.

Bluebirds that do not partake in migration are likely to re-mate with the same companion, even though pairs do not seem to engage after the mating season.

How To Know If a Bluebird Pair Is Official?


When you see both, a male and female Bluebird mingling and are observed together in general, it is a sign that they have mated. Arguably the most revealing indicator of a pair having been formed is when both the birds enter a nesting hole or box together.

Just seeing two birds socialize, however, is not enough. Additional pair interactions will determine if the initial relationship will continue as a pair. The male during this time will collect the nesting material for his side of the nest presentation.

The deal will appear to be sealed after the female bird enters the nest and inspects it properly. This shows that the bird is interested in the offer. The female bluebird then approves the display and accepts the nest after which she starts to gather and put in nesting material into the nesting site.


A male exhibits his rejection for the female by pulling apart the nesting material that she gathered in the cavity.

The male can reject the female by removing the nesting resources she brought to the nesting hole. If the male accepts the female as his mate, he will begin to feed her to reinforce his approval of the breeding mate. Then they both enter the breeding hole, validating the breeding season pair formation.

Mating Behavior

The female initiates the mating action. The act of luring the male is called a female's solicitation posture. 


You will be amazed to know that while the male initiates the bond formation, the female takes the next step. She kneels when perched, maintaining her back straight; lowering and flapping her wings. The male bluebird climbs on the female’s back and attempts genital contact.


Bluebirds’ mating act itself lasts for about 5 seconds on average.

The majority of copulations occur on perches. Males attempt to get on top of females inside the nest, but at times these attempts at mating are fruitless since females do not exhibit interest in what the male built for the females.

During the mating season, which lasts from May to July, the female produces one to two broods. Typically, each clutch contains five eggs. In the meanwhile, the incubation phase lasts between 12 to 18 days.

Exceptions In Mating for Life

While it was always assumed that this kind of bird was monogamous, a new study has revealed that this isn’t always the situation. If you’ve ever compared committed interpersonal relationships to a pair of bluebirds, you might be shocked at how different their relationships are.       

Nesting Failure


One of the most common reasons why bluebirds may not mate with the same bird is a nesting failure. More than half of the failed nesting pairs will swap partners in the hopes of a fruitful nesting effort with a new mate. This is because the mates blame their partners for the lack of results.

While partners are more likely to stay together if their last nesting was successful, it is not required.

Backyard blue birders have statistically recorded many unsuccessful nesting attempts involving the same couple. This means that nesting failure does not mean that the couple will surely change their mates. They may still stick together and try for a successful brood.

Multiple Mating

Scientists have realized that bluebirds no longer have a single mate. Although the ladies are socially monogamous, they are capable of mating with many males. It has been observed that they may have several broods from various partners at times.


You must be wondering what the basis for this claim is! There is research that suggests that females have mated with multiple males. According to that research, 19% of bluebird chicks were not linked to their presumed dads, while 30% to 60% of specific nests include offspring from multiple male mates.

There are ways to confirm that the same female delivered all the eggs laid in the nest. One female will not give multiple colored eggs. However, the presence of eggs in the same nest does not always imply that they were laid by the same parent.


Eastern Bluebirds mostly only form a pair with other birds if one of their partners dies. Shockingly, finding and mating with a new partner may occur a few long minutes after one bird from the pair dies. This depends on the timing of the death of the partner.

During the breeding season, both parents have specific roles to play. The absence of anyone at a particular time can be detrimental to the health of the brood. This is why it is often essential to find another alternative as soon as possible.

The female builds the nest and incubates all the eggs. However, she needs a male to stand guard and provide her with food. If she regularly leaves the eggs to perform these tasks herself, it may lead to poorly incubated eggs that will not hatch. This is why she needs another mate.

Why Do Female Bluebirds Multiply Mate?

In many instances, the female eastern bluebird's propensity of multiplying her partners is believed to be helpful rather than destructive.


Eastern female bluebirds engage in multiple mating due to various reasons. All reasons, however, are related to the females finding a better suitor for themselves. Either way, broods carried by different males are thought to develop healthier and thus have a better chance of survival.

These reasons do not seem justifiable enough to encourage dishonesty but are regardless of why female bluebirds choose to have multiple mates. You must remember how the females find their mate. The males lure them to a nesting site, bring them nesting resources, and flirt with their wings.

It is the female that makes the decision and chooses the male to mate with. However, most of them do not get the opportunity to see all possible partners before choosing one. A female may select a mate from a small group, but a better partner may arrive the next day.

Wondering what a better partner may mean for a female bluebird? Here are a few examples:

  • The selected partner might not have the most extraordinary territory or nesting location.
  • The selected partner may not have the most exemplary parasite-fighting DNA.
  • The new partner may be able to provide better care for her offspring. This happens especially after her initial spouse leaves the nest for an extended period.

Does this apply to all bluebirds, though? No, it does not.

When their male partner is absent in the nest, western bluebird females generally chase male intruders away. To fight off other men or assault a male’s breast, they employ display signals. Many males have tried to participate in extra-pair copulation, but the females have refused.



Several studies have discovered similar behavior in a variety of bird species. Two findings have been observed related explicitly to their geographical locations. It also shows how mating outside their marriage is not a desire but more opportunistic behavior.

The proportion of fledglings sired by more than one male is more significant in highly populated Bluebird regions where mating regions are next to each other than in less densely populated Bluebird locations. This is because options are available for the female that can tempt her into switching for a better site.

Other than the region’s population, the quality of the area also influences their loyalty to marriage. Birds must fly outside their breeding territories to get food if their breeding grounds are of poor quality.

There are more chances that females who ventured outside during their reproductive phase in a low-quality domain will develop extra-pair copulations.

Male Bluebird and Multiply Mating


It may be alarming to understand why males agree to be one of the multiple partners because they are known to be aggressive and territorial about their families. There are two males involved in this multiply mating technique: The initial spouse and the new candidate.

The new candidate approaching the already mated female has his reasons. This male has failed to find a single female, and his chances are now slim. He has options between:

  1. Sharing a female with another male
  2. Challenging another male for his territory
  3. Replacing a male who has died or abandoned the nest for good


The adult life expectancy of bluebirds is reported to be poor. Therefore, many females become widowed or are left deserted.

A bluebird’s aggressive nature is often displayed when the initial suitor finds his female getting too friendly with another male.

If their female partners’ gazes wander, these males easily detect and defend their spouses if they’ve been fooling around. One of the birds may get disabled or die as a result of the battle.

This conduct is mainly in the case of western bluebirds. During the receptive phase or when females consent to copulate, mates who are already in a relationship usually keep a careful eye on their female companions. Extra pair copulations are less likely as a result of this conduct.


Keep Reading!

Bluebirds look to be entirely dedicated to one other, yet they do not stay together indefinitely. In a long-term study of Western Bluebirds, birders discovered that the vast majority of them remain together for the rest of their lives.

Although no similar studies have been done on Eastern Bluebirds, field data suggest that around 95% of them form a pair for life. The other reasons why they may choose to have more pairs are unsuccessful broods, better territories, and lack of options for the males.

Are you interested in reading up on other birds’ mating habits? Here’s a post you can read to identify whether pigeons mate for life or not.

Do Pigeons Mate for Life? Birds True Love

Very few birds form monogamous, lifelong bonds. Pigeons are one of them! Keep reading to explore more about the endearing, strong bond of pigeons.

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By David A. Swanson

Bird Watching USA

My name is David and I'm the the founder of Bird Watching USA! I started Bird Watching with My father-in-law many years ago, and I've become an addict to watching these beautiful creatures. I've learnt so much over about bird watching over the years that I want to share with the world everything I know about them!

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David A. Swanson Picture

David A. Swanson

Bird Watching USA

My name is David and I'm the the founder of Bird Watching USA! I started Bird Watching with My father-in-law many years ago, and I've become an addict to watching these beautiful creatures. I've learnt so much over about bird watching over the years that I want to share with the world everything I know about them!



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