sciencetech-blog

comments

A rare red and grey bird whose plumage is split into two halves has been found to be half female and half male that does not sing.

The unusual northern cardinal was first spotted in Rock Island, Illinois in 2008 and has excited ornithologists for years.

Now scientists who have been studying the bird say it is an example of a a condition known as bilateral gynandromorphism.

The split-sex northern cardinal has bright red male plumage on its left and drab female feathers on its right

This means that it is a split-sex bird, with the bright red colour of male northern cardinal on its left side and the brownish grey of the female on its right.

This occurs when the sex chromosomes in its cells are split unevenly during very early development after the egg is fertilised.

However, despite its striking plumage, the split-sex bird has a rather lonely life, according to the researchers from Western Illinois University who have been following the birds movements.

They said that it never managed to find a mate nor was it ever heard to sing or call.

However, it was also not persecuted by other cardinals and instead seemed to be largely ignored.

It is not clear, however, whether the split-sex bird also carried two sets of sexual organs.

Male northern cardinals usually have bright red plumage (left) while females are a drab grey or brown (right)

Professor Brian Peer, a behavioural ecologist who led the study, said: 'The bird exhibited the typical bright red color of a male cardinal on the left half of its body, and the dull brownish-gray appearance of a female cardinal on the right half.

'We observed the bird more than 40 days, mostly in the vicinity of bird feeders.

'It was never paired with another cardinal, was never heard vocalizing, and was not subjected to any unusual agonistic behaviors from other cardinals.

'These observations are among the most extensive of any bilateral gynandromorph bird in the wild.'

Male northern cardinals (above) usually mark out their territory with whistled songs but the split-sex bird was not found to make any vocalisations during the period that the scientists were studying the animal

Gynandromorphs most commonly exist among insects such as butterflies but are also known to occur in birds and crustaceans.

However, few scientists get to study them in detail in the wild.

Northern Cardinals so called due to the bright red plumage that the males develop, which are said to resemble the scarlet vestments worn warn by Catholic Cardinals.

They tend to be found in woodlands and gardens in the eastern United States and Mexico.

Measuring up to 8.3 inches, it mainly feeds on insects and fruits.

The male birds usually mark out their territory by singing and will court females by feeding them seeds from their beak.

Their song tends to be a loud clear whistle that are repeated several times while cardinal pairs also use a chipping noise to locate each other.

It is not clear why the split-sex northern cardinal did not make any vocalisations but it may be partly why it tended to be shunned by other birds.

It is the second time a gynandromorph cardinal has been sighted, with one in 1969 reported to have the opposite plumage with the male's bright red colouring on the right and the drabber female feathers on the left.