And now for something completely different, a little chicken anatomy and physiology
Chickens have a third eye lid a nictitating membrane it moves sideways across the eye, from the inner corner of the eye to the outer; here is one of the white leghorns taking a drink from the pond,
I’ve unintentionally pressed the shutter when the membrane was across her eye, she normally looks a bit brighter eyed than this; we humans have a vestige of the membrane still remaining in the inner corner of our eyes, isn’t evolution clever.
some birds fly with the membrane closed, it’s thought that it helps protect the eye from dust and grit, its transparent so they don’t crash, sort of Biggles goggles for birds
The lower eye lid of the chicken is more mobile than the upper, they ‘blink’ with the membrane, closing the eyelids ‘proper’ for sleeping, this is Thing One basking in the sun.
Birds have developed a flock of adaptations to suit their needs Woodpeckers tighten their nictitating membrane a millisecond prior to their beak impacting the trunk of a tree in order to prevent their eyes from leaving their sockets
I think that is so cool,Tom thinks it is ‘mint,’ as I imagine, does the woodpecker.