Intersex Wood Duck in Oregon

Intersex -- The condition of being intermediate between male and female

111513

This presumed intersex Wood Duck was photographed at Dawson Corporate Park in Hillsboro, Oregon 15 November 2013. Superficially it looks like a adult male, but the white around the eye, all-dark bill, iridescent pattern on the mantle and coverts are characteristics of an adult female. (Photo by David Irons)

A few weeks back, a birding acquaintance of mine sent me photos of a Wood Duck that he had photographed at Dawson Corporate Park in Hillsboro, Oregon about 15 miles west of downtown Portland. The duck displayed a plumage that left him scratching his head. In his email he wondered, "is this a young male or maybe a hybrid?" It was neither. Almost immediately, I recognized that it showed a mix of both female and male characteristics, which led me to conclude that it was probably an intersex Wood Duck.

Intersex ducks are fairly well known and if you poke around you can find a fair amount of information and many photos of intersex birds on the Internet. However, in one aspect, gender-challenged ducks are different from other intersex birds.

In most bird families, the female plumage aspect is the default appearance. Like humans, the production of sex hormones wanes in birds as they start to age. This results in males taking on a more female-like appearance as they go through annual molt cycles. In ducks, it's the exact opposite, with older females gradually taking on the appearance of the male.

I visited the Dawson Creek ponds on 15 November 2013 and refound the bird. While there, I ran into another local birder, Steve Nord, who told me that this individual has inhabited this location for about five years. It's hard to know if there is a typical age when the transition starts to occur, but the account below, excerpted from a 1992 Dutch Birding article, chronicles the transition of a hand-raised female Mallard. 

On 12 August 1977, four deserted Mallard Anas platyrhynchos ducklings were found and subsequently hand-raised [and ringed; RvdV]; they fully matured and lived for many years as garden pets in Goes, Zeeland. After c 10 years, one of the females gradually started to show male plumage and bare part characters. Within the group (now consisting of seven birds), however, the female still behaved as a females\ and was also treated like a female by the other ducks (which usually is not the case). The bird died on 3 September 1991. Dissection revealed that the left ovary and part of the oviduct were cysteous, possibly as a result of age. The right ovary, however, was still in its normal embrynic state. Birders are regularly confronted in the field with ducks that show incompletely developed adult male plumage characters. Although these are often moulting or juvenile birds, there is a possibility that they are females showing male plumage and bare part characters due to an ovarian abnormality."  (http://fog.ccsf.edu/~jmorlan/feb00.htm)

111513

Here is a typical male/female adult pair of Wood Ducks photographed at Dawson Creek Corporate Park in Hillsboro, Oregon on 15 November 2013. Note the white pattern around the eye of the female (rear) and compare that to the intersex bird above. Also, note the bill color, the paler, cleaner-looking flanks and the solid black rather than iridescent coverts on this male and compare that to the same aspects of the intersex bird. (Photo by David Irons)

Taking a closer look at the ducks at your local duck pond is likely to reveal a Mallard or perhaps another duck that exhibits the appearance of an intersex bird. Look for  birds with male plumage and a female bill pattern. Over the past two years I've seen at least two presumed intersex Mallards. Both had some green on the head, some gray on the flanks and yet the bill was a mix of orange and black typical of a female, rather than a solid yellow-green straw-colored bill of an adult male. Several examples of presumed intersex Mallards can be seen at the link below:

http://users.utu.fi/hlehto/photo/color/anapla_koirasnaaras.shtml 

Literature Cited:

Post J. N. P. and E. J. O. Kompanje 1992. Uitwendige geslachtsverandering bij vrouwtje Wilde Eend. Dutch Birding 14 (4): 131-134.

1

Thank you for this learning and the genetic aspects. bd

2

I believe that the term ‘intersex’, used to define these aging birds is pretty silly and not at all condusive to a proper definition of the phenomena. The term ‘fauxsexed’ would seem to be far more descriptive and scientifically fitting.

3

Impensable, je ne connaissait pas ce site, vous voila dans mes favoris !
Broker En Ligne http://www.etiurl.com/knzj

4

Whatrrrs your opinion would probably look most effective aided by the significant recipe?No Inch At one time he is happen to be group becoming supper stylist, it’s difficult in order to snub that will spoonful with peas!
michael kors fake http://www.motws.org/fakemichaelkors/

5

Impensable, je ne connaissait pas ce site, vous voila dans mes favoris !
Gagner de l argent bourse http://www.gagnerdelargent.tv/

6

but yet Nokia is aware that few are going to throw away ones own new iphone 4 and even Operating system phone for that Lumia. Now, there is certainly Here.
michael kors outlet store http://www.westmontfarmersmarket.com

7

That i didn also apply for which often. Yet the lenght about my personal forearms were actually numerous, the sides ended up in some put (want my best fleece was being sent internally).
michael kors fake http://www.lukecole.com

8

Contribute arranged hot sauce recipe in order to griddle, and additionally prepare dinner 4 moments as well as until firm and also heavy brown leafy colored, stirring continuously.
michael kors factory http://www.atlanticbooks.com/mkfactory/

9

Meat Daytime, each of our decks express directions, photo selections, characteristics, the Floor Drive shots plus much more!
babyliss pro perfect curl http://www.olddog.co.uk/procurlbb.htm

10

Police prefer any person who will surely have seen what went down to get hold of individuals.
babyliss curl secret http://www.phasepatch.co.uk/procurlbb.html

11

BirdFellow – Birding services, social networking, and habitat conservation
La croissance de Nike Air Max obtenir une partie http://www.solutions4playgrounds.co.uk/include/news.asp?id=73

12

In Hong Kong in the initial introduce, most people can second-hand the actual apple company iphone on a turn a profit, deep sufficient to pay for their contact plus the A documents payments.
babyliss curl secret http://www.phasepatch.co.uk/secretcurlbb.html

13

Penney, Meijer, Shelf Space, Sears, Jogging shoe Show, Focus, together with Wal Mart coming from Summer 2005 via September 2010 meant for $10 that will $25.
babyliss curl secret styler 2667u http://www.thefernleahotel.co.uk/curlsecret.html

14

This footwear can be a throwaway made Avoi “water” blockage and are developed to look like a car / truck.
michael kors fake http://www.martincomp.com/michaelkors/

15

and even Pagoda Unusual Boot Ltd. resulting from a choking Opportunity. The actual sneaker comes with decorative added wheels that are able to disconnect, baring all your choking possibility in order to children.
babyliss curl secret styler http://www.squashsite.co.uk/2009/posters/secretcurl.htm

16

BirdFellow – Birding services, social networking, and habitat conservation
Nike Shoes Approach to Distinguish True In addition to Incorrect http://www.myrnamanornorth.com/photos/page.asp?uid=13

Post a Comment

Name Valid Error
Email Valid Error
Comment