I think that when this (rare event) occurs, it is usually divided sex across the mid line. So to that extent it is not unusual. It occurs in many types of animals,
other than birds.
Several internet references to this. See for example: https://io9.gizmodo.com/5810962/bilateral-gynandromorphism-a-fancy-way-of-saying-youre-literally-half-male-and-half-female?IR=T
From: John Layton [
Sent: Tuesday, 4 September, 2018 7:12 AM
To: Canberra birds
Subject: [canberrabirds] Straight down the high-diddle-diddle
I seem to remember that several weeks ago there was mention/discussion about gynandromorphism. Accordingly, check out this androgynous chick from Peter Slater’s sumptuous
book, Australian Birds – a collection of paintings and drawings.
