Birds Changing Sex (1 Viewer)

glaciermint · Feb 19, 2007

Among the mountain of bird books available, one of the older ones 'The Readers Digest Book of British Birds' is perhaps overlooked but is worth a perusal for some of the interesting sections on the life of birds.

Having owned the book for many years I was recently browsing a section on 'bird society' and came across a paragraph which intrigued me.

Apparently in nearly all birds only the left female ovary plays a part in producing the egg. If this becomes damaged, diseased or inactive for any reason the right one takes over (nothing untoward yet), but as a testicle!
The female who has just produced a clutch of eggs then becomes the father of the next clutch!

Apart from imparting this information to anybody who may be as intrigued as I was I wondered whether anybody has any further information to add?

Does the plumage change where this is an obvious feature in the species concerned?
Does a male vocalisation develop?
What happens if a male damages a testis?

Comments welcomed with interest

pete woodall · Feb 20, 2007

In birds, unlike mammals, males are the dominant sex so that if a male looses his testes, he does not change sex - unlike the female as you indicate.

There is an old English saying that sums this up (with apologies to those ladies who might whistle):

A whistling maid, and
A crowing hen,
Are fit for neither
Gods not men.

Cheers

Peter

dtpavlik · Feb 22, 2007

So is there evidence of female birds displaying male characteristics? I have not heard of this before and am very interested in this.

guernsey_dave · Feb 22, 2007

dtpavlik said:
So is there evidence of female birds displaying male characteristics? I have not heard of this before and am very interested in this.

A friend of mine owned a female Golden Pheasant (dull brown job) which at old old age changed its plumage to that of a full adult male.

Kolya · Feb 22, 2007

Then there are Phalaropes . .

Where females sport the more dynamic/colorful markings and to a certain degree, switch parenting roles with males . .

I always wondered how this behaviour came about . . I wonder if this gonad anomaly became regularly codified into their genetic makeup . .

This is partly why a I love being a birder . .the sheer number of questions and unanswered ones at that!

Anybody know anything more about Phalaropes and the apparent gender role reversal?

Kolya

pete woodall · Feb 23, 2007

Hi all
Ther gender role reversal of Phalaropes, Painted Snipe, etc, is different to actually changing sex that started this thread.
Glaciermint quoted a souce that described the process. In most birds (exceptions are birds of prey and kiwi) only the left ovary develops and the right remains an undifferentiated gonad. If anything (like a tumor) stops the left ovary from producing oestrogens, the right gonad develops into a testis or ovotestis, produces testosterone and this leads to the normal male secondary sex features - male plumage and vocalisation, etc.

Things can be more complicated. In the case of a Ring-necked Pheasant (presumably the same applies to Golden Pheasant), female assuming cock-feathers is not always due to changes in the gonads and may be due to hormonal imbalance.

I don't know much about the situation of role reversal in birds but I do know that in the Spotted Hyaena, which also has dominant females, the females also have very high levels of androgen (male) hormones, a very large clitoris and a "false" scrotum.

OK too much information - I'll leave it there.

KnockerNorton · Feb 23, 2007

As mentioned, some old females can sometimes start showing male characteristics in plumage. Chaffinches are obvious ones, where the females start getting brighter plumage, but it usually looks like a washed out version of the male.

mattie · Feb 23, 2007

when i used to keep bantams i had a rhode island hen that used to crow like a cockerel and even used to try and tread the other hens but it still layed eggs .

Sancho · Feb 23, 2007

mattie said:
...used to try and tread the other hens... .

This is a brilliant and bizarre thread. Tell me, Mattie, does ´Tread the other hens´mean what I think it does?

KnockerNorton · Feb 26, 2007

Sancho said:
This is a brilliant and bizarre thread. Tell me, Mattie, does ´Tread the other hens´mean what I think it does?

Treading is a fairly common term for bonking, yes. It comes from the male 'treading' on the female's back. Bird breeders useit a lot.

Sancho · Feb 26, 2007

Poecile said:
Treading is a fairly common term for bonking, yes. It comes from the male 'treading' on the female's back. Bird breeders useit a lot.

Thanks, Poecile! I'll use that!

talon_dfa · Feb 26, 2007

mattie said:
when i used to keep bantams i had a rhode island hen that used to crow like a cockerel and even used to try and tread the other hens but it still layed eggs .

I have heard of cases where old hens (after growing crown & crowing etc) actually fathered chicks as well...

Rasmus Boegh · Apr 19, 2007

An older thread dealt with this subject, too:

http://www.birdforum.net/showthread.php?t=42348

I don't have any reasons to modify the comments in post #11 in above thread (except for a minor modification on my SRY comment, but that is only indirectly related to this subject). I have been unable to find any confirmed evidence of a true sexual change in birds (i.e. starting as a functional male and becomming a functional female or vice versa), and as far as I can see it would contradict some of the basics in avian biology. Still, if anyone have *confirmed evidence* of a true sexual change in birds, I'd certainly appreciate to know about it.

KnockerNorton · Apr 19, 2007

Rasmus Boegh said:
An older thread dealt with this subject, too:

http://www.birdforum.net/showthread.php?t=42348

I don't have any reasons to modify the comments in post #11 in above thread (except for a minor modification on my SRY comment, but that is only indirectly related to this subject). I have been unable to find any confirmed evidence of a true sexual change in birds (i.e. starting as a functional male and becomming a functional female or vice versa), and as far as I can see it would contradict some of the basics in avian biology. Still, if anyone have *confirmed evidence* of a true sexual change in birds, I'd certainly appreciate to know about it.

it's physically impossible for a functional male to change into a functional female. It could occur if the bird was mutated to begin with, eg hermaphroditic. But that's all.

Mark Harper · Apr 19, 2007

I have heard that old female Booted Racket-tails in Ecuador are in appearance like immature males. This is thought to be an increasingly common phenomenom as hummingbird feeders prolong the life of the birds.

Graham5152 · Mar 15, 2014

Turkey sex change

For the last year I had 3 turkeys running without a stag. These are several years old and have all been laying eggs. After Christmas I bought a 2 year old stag and 2 young hens. This week the 3 older hens have all changed into stags. What I need to know is will they change back again or are they now fixed as stags?

Oldgal · Feb 17, 2016

I have had a pair of red-breasted woodpeckers coming to my feeder for 4-5 years, year round. Apparently the cat got one of them several months ago. Since I kept seeing the female at the feeder, I presume the male met his demise. But recently, I am seeing a male at the feeder, but not the female anymore. Is it possible the "Widow Woodpecker" has morphed into MR. Woodpecker? Or does the widow have a new suitor?

Peter C. · Feb 17, 2016

Oldgal said:
I have had a pair of red-breasted woodpeckers coming to my feeder for 4-5 years, year round. Apparently the cat got one of them several months ago. Since I kept seeing the female at the feeder, I presume the male met his demise. But recently, I am seeing a male at the feeder, but not the female anymore. Is it possible the "Widow Woodpecker" has morphed into MR. Woodpecker? Or does the widow have a new suitor?

I can`t say that it is completely impossible for a woodpecker to change sex, but that is certainly not what you are seeing here. Woodpeckers only moult once a year, in the fall, so there`s no way for any (putative) sex change to have been expressed by this time. The earliest you might see such a change would be next August/September.

What you have here is an interloper, who may (or may not) have driven the "old" female away.

P.S. - what is a a Red-breasted Woodpecker? Do you mean Red-bellied, maybe?

Cheers,

Oldgal · Feb 17, 2016

The Widow Woodpecker

Thanks for the info. Yes, I did mean red-bellied woodpecker. Should have checked my notes.

Andy Adcock · Feb 18, 2016

Rasmus Boegh said:
An older thread dealt with this subject, too:

http://www.birdforum.net/showthread.php?t=42348

I don't have any reasons to modify the comments in post #11 in above thread (except for a minor modification on my SRY comment, but that is only indirectly related to this subject). I have been unable to find any confirmed evidence of a true sexual change in birds (i.e. starting as a functional male and becomming a functional female or vice versa), and as far as I can see it would contradict some of the basics in avian biology. Still, if anyone have *confirmed evidence* of a true sexual change in birds, I'd certainly appreciate to know about it.

Surely a fully functional gender change is impossible, chromosonal arrangement would remain the same?

Displaying charcteristics is one thing like a bodybuilder developing breast tissue if he's on an oestrogen based steroid but he's still just a man with breasts?

The example of a Bantam fathering chicks is unlikely, there would be no sperm production and presumably no delivery mechanism either.

I stand to be educated further!?

Andy

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