Gender dimorphism

The difference between the sexes is not obvious at the Lineolated Parakeet. The feather markings of the female are said to be weaker altogether, the shoulder mark and the black tips of the tail feathers are paler, smaller or totally missing. De Grahl (1985) writes: "The presumption, I made many years ago, that male birds are showing both tips of the median tail feathers black-coloured, in contrast to the female, could be confirmed due to several breedings by W. Sigrist from Switzerland. He searched for his breeding pairs using only these features."
On account of his breeding experiences, Bauer (1990) agrees, that the sexes can surely be distinguished. He states the top sides of the tail feathers, which show an about 5 cm wide black tip at the females, as the safest distinguishing feature. In contrast, the male should have this black colouration up to the upper tail coverts. But he points out that the elbow, also at the female birds, sometimes shows "a large black marking". As further difference Wagner states the dark plumage lines which are thinner at the female. Furthermore, the "rump feathers of the male are essentially blacker" and they are showing "large black dots".
Low (1983), in contrast, considers the determination of the gender to be difficult, as the plumage of the male and female of some of her breeding pairs were more or less identical. So, a birds considered female turned out to be male after its death. Three more hens, which according to Low "were labelled as females" underlined the insecurity of gender determination as well. Only one was looking like described before, "the other two had some black on the tail and wide black edges to the wing-coverts."
The statements of the more recent literature are rather pointing at the second view (among others Ehlenbröker 1994) as well. There also is the method of touching the pelvic bone as it is done for example with Love Birds, but for doing this you need a lot of experience. At a sexually mature female the pelvic bone is more wide-set than at a male (Ehlenbröker 1994).

Below please find a few examples of Lineolated Parakeets with known gender:

Female Firstly, you see a classic example of a female (right picture, blue colour morph). There is no black at all at her tail feathers. The marking of the upper tail coverts is a little bit weaker as in direct comparison to the following cock (left picture below; wild coloured).
Nevertheless, this splendid specimen of a male does not have tail feathers broadly edged with black, as one would expect. They appear somehow "washed-out". Furthermore, the black does not reach up to the upper tail coverts.

Male It is obvious that these two Lineolated Parakeets are a couple. The male feeds the female regularly, courtship and mating can be observed. During breeding season, the cock defends the sleeping place and other areas of the aviary against unwelcome intruders which can also be members of the same species. The couple conjointly looks for a nesting place and you can hear the typical "call notes" of the cock as well as tender couple contact sounds. At night, both Lineolated Parakeets sleep together in the same sleeping box.
Although one can not be sure on account of the tail marking that the mail is indeed male, according to its behaviour I never had doubts about this. As an "evidence" this couple produced fertilised eggs in spring 2003.

In contrast I was not sure at all concerning the gender of the following two birds.

Male This wild-coloured, hand-fed representative of the Lineolated Parakeets (right picture) was sold by its breeder together with a male as a hand tame couple. It was assumed to be a female. By the time both got sexually mature, they had to be separated on account of acrimonious fights. However it was never thought of that it could be a male, too. Certainly, the median tail feathers are clear but only small black edged. The other body marking is also not essentially distinct. Obviously, it seems to be a female. This bird spent the following year together with a cockatiel and two bigger parrots (of different species) until it got to my small flock in May 2002. Due to the descriptions of the previous owner I had a DNA analysis made for gender determination. This examination showed that it was a male.

Male This makes the coupling of this Lineolated Parakeet with the blue Lineolated Parakeet shown on the left even more odd. At that time I got it as a partner for the apparent female. On account of its almost totally black median tail feathers and the more than clearly distinct plumage marking it definitely is a cock. But also among these two animals it came to copulating attempts. However, there was no partner feeding. In this partnership, the blue bird took over the role of the female. This was going well for a time, until the inferior mate, the blue male, tried to break out of this role. Because of that, the aggressions among them became fiercer and fiercer, so that I had to separate that "couple".

However, it must be stated that none of these two birds ever tried to take away the female from the above-mentioned male. In the same way, they did not try to get in closer contact to the female which was in the aviary as well. Therefore, the coupling of these two parakeets was voluntary.

In conclusion I may point out that all of my Lineolated Parakeets (of course with exception of the Lutino and the Creamino) have a black shoulder. This is also more or less of the same size and blackness at all of them. At least, you can't infer the gender of my birds from their elbow colour.

The young birds of the Lineolated Parakeets are sometimes coloured paler, the beak and the legs are lighter than those of the adults and the forehead shows a light blue glimmer. However, you can find a blue gleam at the adult animals, too, at the front head as well as at the primaries or around the shoulders and the elbow. Because of that Bauer (1990) is of the opinion that you cannot definitively distinguish the squabs from the adult birds.

The sub-species of the type form, the Barred Parakeet (Bolborhynchus lineola tigrinus) shows a darker plumage as the B. l. lineola. At the largest part of the plumage the black edging is more distinctive, especially conspicuous is the extensive black shoulder (Arndt; 1986). The iris shall be brownish, feet and beak are darker. The Barred Parakeet was imported only in a small number to Europe. Due to the small amount of distinguishing features to the type form it is not to be find out anymore, if there are still pure-bred specimen in Europe. Probably a large part of the Lineolated Parakeets living in Europe are hybrids of both sub-species.