Members of the parrot family, cockatiels (Nymphicus hollandicus) are a beautiful species that has become one of the most popular pet birds in the world. Unlike zebra finches and other species whose gender is immediately apparent, cockatiels carry their gender identity closer to the vest. Distinguishing between males and females is not always easy, so consider several criteria to find the answer.
The most accurate way to determine the gender of a cockatiel is to have a veterinarian examine the bird internally. While cockatiels have considerable internal differences, they have few external differences aside from minor differences in plumage. Unlike many other species that bear fanciful appendages, both cockatiel genders have crests. Rather than a form of sexual advertisement, the crests help cockatiels to communicate with each other.
In the wild, male and female cockatiels are clad in similar, gray colors. This earth-toned coloration helps cockatiels camouflage themselves from predatory birds while they forage for acacia seeds on the ground. The only obvious difference in color between the genders is the orange cheek patches of the males, which are brighter than those of the females and encircled in a ring of white; the females lack the white ring. Additionally, males may display white feathers near their shoulders. In contrast to standard gray cockatiels, those displaying color mutations are often more difficult to distinguish by color; different mutations carry their own gender clues. One trait that tends to appear in most color mutations is subtle barring of the tail, which signifies that the animal is a female.
Male and female cockatiels exhibit some behavioral and social differences. For instance, males commonly sing, chirp and vocalize, but females are often quiet companions that are more likely to act aggressively or even bite. Pair bonding is an important aspect of life for these often-monogamous birds. Males often engage in a series of bold displays when courting females. During these displays, males may lift their wings, pound things with their beak or walk with an exaggerated strut. Males may also sing songs to court females, while females make soft vocalizations and raise their tail feathers when receptive.
Some cockatiel color mutations are sex-linked, meaning that the genetic mutation occurs on one of the gender-determining chromosomes. The gender determination system for birds is opposite of the system in mammals; male birds have two "X" chromosomes, while females have an "X" and a "Y" chromosome. If you know the genetic makeup of the parents, you may be able to infer the gender of a baby cockatiel, depending on whether it displays the mutation. For example, if the father was a lutino – a mutation that only occurs on the "X" gene in birds – and the mother was not a lutino, any chicks produced by the pair that display the lutino mutation must be females. This occurs because while the sex-linked trait is recessive, females do not have a normal "X" chromosome to dominate the mutant gene. By contrast, males can carry the gene, without displaying it.