Budgies reach sexual maturity at around 4 months of age. At this point, male budgies are likely to show significant interest in mating.
Females are unlikely to reciprocate, with most showing no interest in breeding for 10-12 months.
So, observe male and female sibling pairs once they reach 3 months old. A male of this age will detect his sister’s estrus cycle, but a young female may react aggressively to his unwelcome attention.
Do Budgies Mate with Siblings?
For the first year of her life, a female budgie usually avoids breeding with a male sibling.
Biological Reviews posits that birds recognize their siblings through familiarity and frequent exposure. What’s more, younger females are rarely interested in mating anyway.
However, this won’t deter a hormone-driven male. As per Animal Behavior, male birds show no bias toward their offspring, so the same applies to a potential mate.
A female budgie may instinctively reject the advances of a sibling, but this isn’t guaranteed.
After a year, two budgies are less likely to recognize each other as siblings. This makes sharing a cage more problematic, as the risk of the two birds mating increases.
According to Science, if the male sibling shows intelligence and problem-solving, his sister is more likely to be receptive to breeding.
Signs of courtship between two budgies include:
- Constant preening
- Feeding each other
- Male tapping the female’s beak with his own
- Female lifting her tail and wings
If you notice these actions and behaviors, separate the two budgies until the female completes her estrus cycle. You may need to consider permanently housing the birds in separate cages.
Effects of Inbreeding in Budgies
Breeding sibling budgies has negative consequences for the chicks. Zoo Biology stated that some chicks will be healthy while others will develop physical defects.
Issues that have arisen in chicks sired by budgie siblings include:
- Failure hatch from the egg
- Malformed limbs or wings. Some inbred budgies are born with one leg
- Blindness or being born with one eye
- Cognitive and coordination difficulties
Sadly, some private breeders continue to mate brother and sister pairs of budgies to maintain rare colored budgies that fetch a higher price.
How Do Budgies Avoid Inbreeding?
Trends in Ecology and Evolution stated that wild birds adopt sex-based dispersal upon reaching maturity. This means that females will flee the nest and travel further afield while males remain to guard the nest.
Once the female reaches a safe distance, breeding can begin with a bird from a different bloodline. This ensures the propagation of the species without the risks inherent in siblings mating.
Captive budgies don’t have this option. The only option for a captive female is to aggressively reject the advances of a male, which will naturally lead to conflict.
If you intend to keep male and female sibling budgies together, separate them while the female is in heat. This is the most failsafe way to avoid unhealthy chicks.
Other steps you can take to discourage inbreeding include:
- Tricking a female into thinking it’s winter by covering the cage and keeping the room silent.
- Discouraging breeding behaviors toward you, such as rubbing or scenting.
- Removing any toys from a cage that a budgie uses to imitate mating.
Spaying or neutering a budgie isn’t an option, as this process is complex and dangerous for birds.
Can You Keep Budgie Siblings Together?
As explained by Proceedings of the International Ornithological Congress, budgies jealously guard their territory, even from their own siblings.
One way around this is to pair by sex. Two males will usually get along in the same cage, but a pair of females are more likely to clash over space.
In theory, two budgie siblings adopted as chicks are the ideal pairing. Assuming the birds were born in captivity, they’ll be accustomed to sharing a cage, so they should peacefully co-exist.
Even if your budgies have bonded and get along well with each other, they sometimes fight over food, water, attention, space, or other valuable resources.
If you adopt sibling budgies, ensure they’re treated equally. As per The Evolution of Begging, budgies will compete for your affection.
So, don’t give one budgie more attention or food than the other, even if it’s more vocal and demanding.
Signs Budgie Siblings Don’t Get Along
If the budgies only display aggression toward each other, it’s a familial dispute between the siblings.
Warnings that two budgies are struggling to live together include:
- Spreading their wings – This is the equivalent of a boxer showing his fists.
- Hissing – Most budgie noises are gentle and shrill, but this guttural sound is a warning.
- Aggressive pecking – Happy budgies will groom each other, but if fighting, pecking will become more aggressive, especially if aimed at the head.
- Biting feet – Budgies never bite each other’s feet unless they show aggression.
- One-sided chasing – Play between siblings will involve the budgies taking it in turn to be chaser and chasee. If one budgie is constantly chasing, it’s an act of domination.
- Refusing to share food or water – The most common cause of conflict in budgie siblings. Ensure each bird has its own food dish and water bottle.
When keeping two budgies, have a second cage on standby in case they clash. Move the more aggressive budgie to this spare cage but keep both habitats within sight of each other.
This allows the budgies to rebuild a bond from a safe distance.
Wildlife Management stated that parakeets hold negative memories for up to two years, so the birds may need some time apart to cool off and forgive each other.
Signs Budgie Siblings Have Bonded
If you adopt sibling budgies at the recommended age of 38-42 weeks old, they’ll likely have already bonded, especially if both are male.
Also, females in an appropriately large cage and mixed-sex pairings can bond successfully.
The following behaviors suggest that sibling budgies have bonded:
- Sitting together, often on the same perch. If the two budgies willingly touch, they’re close.
- Eating from the same bowl and choosing to feed at the same time.
- A male may opt to feed a female.
- Singing in tandem or for each other.
- Preening and grooming each other.
If your two budgies largely ignore each other but live in contentment without outward signs of aggression, they likely get along fine.
Budgies like the company of their own species, and pairing siblings is a great way to provide this companionship. Just be mindful of the risk of paring a brother and sister budgie in the same cage.