Intersex Teal? (1 Viewer)

[Andrew1998]

Came across this interesting Eurasian Teal recently with somewhat unusual features. At a distance it may look like a moulting Teal drake but I suspect this bird is intersex-a condition where the bird shows features of both male and female plumages. Striking plumage details were the weak head pattern (brown colour is paler than regular teal+dull female like feathering) plus very thick barring all over the body. Drake teal have thinner bars allowing them to have a more 'uniform' look at a distance whereas this bird is very obviously barred. I've seen pictures of intersex Pintail showing similar, broad barring too. The pale tail patch on the bird is very white looking against otherwise brown plumage, I believe this is a feature of intersex birds. Usually on drake Teal this patch is yellower and has a strong black border. A late moulting 1st winter bird was considered but most of those birds have complete or very near complete adult looking plumage right now. Indeed, this bird was unlike all other Teal in the flock. I don't see any influence from other species to suggest a hybrid.

Link here for interest: Intersex birds (and their confusion with hybrids)

Anyway, hoping for confirmation on this bird. If anyone has any in-field experience of these birds that would be appreciated. Lothian, March 2022.

 

[Joern Lehmhus]

yes in my opinion intersex plumaged teal. what you describe is rather typical.

 

[Andrew1998]

yes in my opinion intersex plumaged teal. what you describe is rather typical.

Cheers Joern, I hoping you'd be able to use your expertise in this field to confirm my sighting.

 

[MacNara]

Is 'intersex' the right term? We have occasional Teal like this where I am. When I asked people more knowledgeable than me, the explanation they gave was as follows.

Strange as it may seem, the male plumage is the default plumage in birds. In females, female hormones suppress this plumage (perhaps to focus energy on egg production; hence why females in species where the male rears the chicks, such as Painted-Snipe are more colourful). But when females age, hormone production drops off (a sort of menopause), and elements of the male plumage can appear. Remember in birds, males are ZZ (i.e. XX) and females are ZW (i.e. XY).

I have never checked this theory, and would be interested if anyone can support it, or alternatively refute it.

 

[Alexander Stöhr]

Hello MacNara,

interesting point. I didnt ever thought of it.: is the word "intersex" a good choice for this?
Please note, that the term "intersex" doesnt mean,that the bird is between a male and a female (which could be concluded if the word is taken as a description).
It stands for the situation,you describe: a female develops some phaenotypical characterstics of male plumage.

But as I understand, the term "intersex" is well established, so its better to accept this word to describe females with variable male features in the plumage, caused by hormone levels (more often in older females, as you said).

A question: can an intersex female change back to "normal" female plumage?

 

[Joern Lehmhus]

Is 'intersex' the right term? We have occasional Teal like this where I am. When I asked people more knowledgeable than me, the explanation they gave was as follows.

Strange as it may seem, the male plumage is the default plumage in birds. In females, female hormones suppress this plumage (perhaps to focus energy on egg production; hence why females in species where the male rears the chicks, such as Painted-Snipe are more colourful). But when females age, hormone production drops off (a sort of menopause), and elements of the male plumage can appear. Remember in birds, males are ZZ (i.e. XX) and females are ZW (i.e. XY).

I have never checked this theory, and would be interested if anyone can support it, or alternatively refute it.

That is essentially true for ducks as far as I know- and for Galliformes--
I wasn´t sure about other birds in this respect.

But therefore I prefer the term intersex plumaged bird.
These birds are not true intersexes but show a plumage in between male and female plumage. So, generally these ducks are females with very low female hormones. In German there is an old term for such birds: "Hahnenfedrig", which you could translate with "cock--feathered".

 

[Tired]

"Intersex" refers to an organism (and it can be any organism) that exhibits a combination of male and female characteristics when it isn't supposed to. It's typically used to refer to an organism having both male and female genitalia, when that's not the norm for the species. Some animals are meant to have both (lots of snails) or to change between both (sequential hermaphroditic fish), so those wouldn't be considered intersex.

I think "intersex plumaged bird" is a good way to be clear about what we're looking at. I'm not sure if it's technically the correct term, but I can easily understand what it means, and in my book that makes it a good term. Unless it's wildly inaccurate for reasons I'm unaware of.

I've read about peahens and chicken hens that grow male plumage as they age. That must be a surprise for the owner.

Another way that an animal can demonstrate both male and female traits is if we're looking at a gynandromorph. A gynandromorph is a chimeric animal, one with two different sets of genes, where one set of genes is male and one is female. Bilateral gynandromorphs are the most striking example, as half of the animal will be male and half will be female, but gynandromorphs can also be mosaic chimeras. A mosaic chimera is what it sounds like- the different patches of genes will be all scrambled up. Chimeras are quite rare, though, so a female bird showing male plumage is probably a hormone shift unless the male plumage is weirdly localized. For example, a cardinal that's half red and half tan, split down the center.