Hi,
I would make the correction that in birds the female is the
heterogametic sex and the male is the homogametic sex. To distinguish
this the sex chromosomes are called W and Z. Thus the females are WZ
and the males ZZ.
Andrew
Greg wrote:
Hi Andrew,
Some years ago while bird banding at Tumbi Umbi, on the Central Coast of
NSW, I retrapped an adult female Golden Whistler that was assuming male
plumage characters. I knew that it wasn't an immature male assuming
adult plumage as the bird was very old (for a small bird) at the time
and had only recently began assuming these characters. Its banding and
retrap history was recorded on a specially designed card. John Disney,
who was the Curator of Birds at the Australian Museum suggested that it
was probably due to the deterioration of the ovaries due to age. I
think that the XX (female) chromosomes become XY (male).
So this phenomenon has been known for some time.
Regards
Greg Clancy
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