Wednesday Walk

To: 'Lindell' <>, 'Canberra Birds' <>, "" <>
Subject: Wednesday Walk
From: Philip Veerman <>
Date: Wed, 16 May 2018 11:57:25 +0000

I can’t be certain but I suggest from that one photo that the Maned Duck is a gynandromorph. That is an abnormality resulting in a bird (or whatever) having a mix of male and female characteristics that may be combined with some oddities thrown in. See below extract from Wikipedia. The idea of a hybrid I guess coming from recent discussions about Mallards, but that is an irrelevance. The white lines on the face and spotted flanks of a female Maned Duck and the other features (especially the dark “mane”) of a male Maned Duck. It is common for gynadromorphs to be different on left and right side. It would be useful to know whether the left side was normal for a male or female.





From Wikipedia, the free encyclopedia


gynandromorph is an organism that contains both male and female characteristics. The term gynandromorph, from Greek "gyne" female, "andro" male, and "morphé" form, is mainly used in entomology. These organisms are notable in butterflies and other insects, where both male and female body parts can be distinguished physically because of sexual dimorphism.



·         1Occurrence in other genera

·         2Pattern of distribution of male and female tissues in a single organism

·         3Causes

·         4As a research tool

·         5In popular culture

·         6See also

·         7References

·         8External links

Occurrence in other genera[edit]

Gynandromorphism has been observed in numerous animal species, e.g., crustaceans such as lobsters and crabs, many birdspecies.[1][2][3][4][5] A clear example in birds involves gynandromorphic zebra finch. These birds have lateralised brain structures in the face of a common steroid signal, providing strong evidence for a non-hormonal primary sex mechanism regulating brain differentiation.[6]

Pattern of distribution of male and female tissues in a single organism[edit]

A gynandromorph can have bilateral asymmetry—one side female and one side male.[7] Alternatively, the distribution of male and female tissue can be more haphazard.

Bilateral gynandromorphy arises very early in development, typically when the organism has between 8 and 64 cells.[8] Later stages produce a more random pattern.[citation needed]


The cause of this phenomenon is typically, but not always, an event in mitosis during early development. While the organism contains only a few cells, one of the dividing cells does not split its sex chromosomes typically. This leads to one of the two cells having sex chromosomes that cause male development and the other cell having chromosomes that cause female development. For example, an XY cell undergoing mitosis duplicates its chromosomes, becoming XXYY. Usually this cell would divide into two XY cells, but in rare occasions the cell may divide into an X cell and an XYY cell. If this happens early in development, then a large portion of the cells are X and a large portion are XYY. Since X and XYY dictate different sexes, the organism has tissue that is female and tissue that is male.[9]

A developmental network theory of how gynandromorphs develop from a single cell based on internetwork links between parental allelic chromosomes is given in.[10] The major types of gynandromorphs, bilateral, polar and oblique are computationally modeled. Many other possible gynandromorph combinations are computationally modeled, including predicted morphologies yet to be discovered. The article relates gynandromorph developmental control networks to how species may form. The models are based on a computational model of bilateral symmetry.[11]



From: Lindell [
Sent: Wednesday, 16 May, 2018 7:58 PM
To: Canberra Birds; ;
Subject: [canberrabirds] Wednesday Walk


A total of 15 Members gathered at the parking area of the North Weston Ponds near the RSPCA on a beautiful Canberra Autumn morning.

We circled the first large pond and observed the numerous water birds perched on the barrier across the middle of the smaller pond. 1 Black-fronted Dotterel was on the concrete drain joining the 2 ponds. There were 16 Pink-eared Ducks along with Grey Teals, Hardheads, Pacific Black Ducks, Coots and Hoary-headed Grebes and a Little Pied Cormorant all adding to the count. Australasian Pipits were seen in the open area to the west of the pond.


The track along the southern side of the river yielded a few lbb's but it wasn't until we ventured along the north side that we encountered a large mff. 2 White-fronted Chats, many Superb Fairy-wrens, Brown Thornbills, Silvereyes, at least 5 Double-bar Finches and more Australian Magpies.

One Australian Wood Duck (Manned Duck) had us wondering if it was a hybrid of some sort, but on closer study it looked to have some odd and re-arranged wing feathers on the right side only (the left side was quite normal). 


All up we recorded 38 species for the day - the full species list is on ebird.



A healthy looking fox was seen across the river near the foot bridge.



Mawson ACT

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