How does breeding occur in birds?

Sexing and reproduction of birds

Many individuals own birds in France, sometimes with the desire to have young. It is thus judicious to know some information on the sexing of these birds and on the management of the reproduction of these feathered animals.

Contrary to our domestic carnivores (dog, cat, ferret) in which it is relatively easy to differentiate a male from a female because the sexual organs are external and apparent, knowing the sex of your birds is not always easy. The external genitalia of the birds are represented by cloacas, which does not allow a male/female distinction. However, like mammals, the internal genitalia (not visible) are different according to sex.

How to sex an aviary bird?

Sexing is essential for breeders in order to form couples, but also for breeding programs, reintroduction programs, for owners wishing to choose an appropriate name for their boarder, and finally for veterinarians in case of sex-related diseases.

For some species of birds, sexing is easier because certain physical aspects of the bird are visually different between the male and female: we speak of dimorphic species. An obvious example is the hen and the rooster.

The differences can be related to :

  • The plumage (example of some parrots such as the Eclectus).
  • The color of the iris for Cockatoos.
  • The size/form/color of the beak or its wax for wavy parrots in particular (blue wax for males and brown wax for females).
  • Or other physical characteristics such as size, presence of particular appendages (such as the developed crest of the cock).

However, these criteria are not always reliable due to the domestication of the birds which has led to physical changes. Moreover, these sexual criteria appear rather late. Finally, a large majority of captive birds are part of the so-called monomorphic species: there is no physical difference between male and female (example of the parrot in Gabon).

The behavior can also give information on the sex of the bird if one is a little bit observant: the male is the one who rides on the female; the male’s song is different…

It takes at least 2 birds to be able to observe such a behavior. But this is not 100% reliable because it happens that birds of the same sex mate with each other if there are no congeners of the opposite sex.

Other sexing methods have therefore been developed to sex birds more accurately and earlier.

  • The chromosome technique

Birds have different sex chromosomes between the male and female (like Mammals). Thus, the female carries one Z and one W chromosome while the male carries two Z chromosomes.

To identify the chromosomes, it is necessary to culture cells from the bird, either from its blood or from its feathers. This method is hardly used today because it is complicated.

  • The technique of endoscopy

This technique is based on the use of a micro-camera that is introduced into the bird through the flank in order to visualize the internal genitals. This method is fast and precise but requires a general anesthesia and a small surgery which can induce stress to the animal. Moreover, it is not always feasible on young animals.

It is therefore often performed today when it is necessary to visualize other internal organs during certain illnesses.

  • The DNA technique

This is the most common method at present and the most recent. It is based on genetic tests that reveal different genes between males and females. To be able to carry out this test, it is necessary either to take a few drops of blood from the bird, or to cut a few feathers from its tail or belly (less traumatic and simpler) or to recover the eggshell of the chick that has just been born. Then these samples are sent to a laboratory which carries out the necessary analyses and gives an answer on the sex in a few days.

This technique can be done at any age, even when it is a chick and is possible for all species of birds.

Reproduction in domestic birds

There are many different species of domesticated birds, each with different breeding characteristics. Generally speaking, birds follow the same stages during reproduction.

The formation of a pair

Putting a male with a female is not a criteria for successful couple formation. Indeed, it is necessary that there is a good understanding between the partners. Some birds, such as parrots, are difficult in the choice of their partner, and it is often necessary to introduce them to several of them. When putting two birds of the opposite sex together to form a pair, one must be vigilant and learn to recognize the signs of misunderstanding: frequent pursuit of one by the other, permanent cries, pecking, injury. These behaviours may be normal when a new bird arrives, but they should not last over time. If this is the case, then it is preferable to introduce a new partner.

On the other hand, it is important to be able to recognize the signs of a good understanding between two birds likely to form a couple: mutual grooming, sharing of food, singing, parade and courtship of the male, resting side by side…


Reproduction periods depend on many parameters such as day length, temperature, feeding, presence of congeners of the opposite sex… The mating period is generally in spring-summer.

Mating occurs in several phases. There may be a courtship parade allowing the male to seduce the female with songs or particular attitudes.

When the female is receptive, the male climbs on the female and puts his cloaca in contact with the female’s cloaca in order to let the spermatozoids pass that will go to fertilize the ovum.

Example of mating between the hen and the rooster

The nest or nesting box

The vast majority of exotic domestic birds require the presence of a nest for the female to lay her eggs. The nest must be large enough to accommodate both the male and female.


The female lays a variable number of eggs, depending on the species (globally between 2 and 8). She then incubates her eggs for 10 to 30 days, depending on the species, leaving the nest only a little, just to feed or relieve herself. Sometimes the male can replace the female and brood for a while.

The hatching

The hatching occurs at the end of the incubation period, which differs according to the species of birds. The chick moves in its egg and manages to crack it in order to extract itself from it. Most of the time, the mother helps the chicks out.

Raising the chicks

Unlike chicks or ducklings, aviary birds give birth to chicks that are not able to fend for themselves. The parents are therefore obliged to feed them: they are said to be beaky. It is important to give the parents an adapted and rich food during this period for a good growth of the chick. Then comes the weaning where the chick is able to feed itself.

In conclusion, sexing is often an essential step if one wants to start bird breeding. New DNA-based techniques are fast, reliable and available at a reasonable cost.

Reproduction of birds in captivity is not always easy. It is necessary to be familiar with the particularities of the bird species you own in order to obtain the satisfaction of seeing small chicks hatch.