What's going on with the eyelids?

[Ozzie_Traveller]

G'day all

Alan and I were walking his favorite lagoon the other day and we came across a bunch of geese / ducks? (and again a 'thanks mate' to Alan for the outing)

What's got me puzzled is that the grey-feathered one as it blinked its eyes became "greyed"
Is this normal? or is something else happening

1)- the grey bird

exif- Panny FZ-300; 1/200s x F8,0; ISO-400; lens at 24x zoom / 600mm FFequiv

2)- the white bird with eyes as I am use to seeing

exif- Panny FZ-300; 1/200s x F8,0; ISO-400; lens at 24x zoom / 600mm FFequiv

As always, feedback welcome
Phil

[AlfandBen]

I think it might be the nictitating membrane or third eyelid.

[David_MC]

Nice shots. It looks like the nictitating membrane (third eyelid) like AlfandBen pointed out.

[Isac]

I have to agree with the 2 knowledgable gent above, because I have no idea. These 2 images are of geese.

[wigz]

That does look odd. The eye doesn’t appear to be closed so perhaps it has been injured

The nictitating membrane is (usually?) translucent and moves horizontally so I don’t think that’s it. It usually makes the eye look somewhat milky. I’ve had a few shots with it closed.

Goose with the nictitating membrane over the eye Stock Photo - Alamy

Phil, thanks for making the effort to drive the camper over through the traffic. Nice shots too.

[AlfandBen]

I must admit I did think it odd but having researched a bit more on good old google I came across this-

"The inside eyelid is called nictitating membrane. It is works like a windshield wiper, can cover the entire eye and is clear. The white eye one sometimes see on certain ducks and geese is feather fluff on the outer eyelid. I believe they have evolved that way to make it appear that the sleeping duck or goose has his eye on you. It is interesting to note that on ducks, and I am pretty sure geese as well, the eyelids close from the bottom up, opposite from ours which close from the top".

Having downloaded Phils image and blown it up it does resemble feathers.

[wigz]

I think you are correct AlfandBen. There is some sort of soft fluffy texture there.

[Ozzie_Traveller]

G'day fellas

As we were walking towards the group of 1/2-dozen birds, all the white birds had their eyes open (as per image) and this grey bird was blinking and the eyes became 'milky'
During the blink, the eyeball was quite visible, but once the blink was done, it reverted to this milky look

All interesting but a little strange to me as an unknown / unskilled birdie
Phil