Ever since my parents first brought in a trio of African Grey parrots into the United States from Nigeria back in the sixties, I have been continuously learning new things about keeping parrots as pets.
One thing I have learned in over thirty years of having multiple pets birds in my home; parrot's are always on their feet, 24/7.
Well, I will admit ET, my sixteen year old Grey does spend an amazing amount of time hanging by a toe or a beak from a bird toy, but when it comes right down to it, a Bird Perch is where his feet are wrapped most of the time.
It is for that reason, the inordinate amount a pet parrot spends standing on a perch, that we understand the need for varying textures, and diameters on these perches to exercise their feet.
Varying textures, not only means using natural wooden branches such a Manzanita to provide different textures, but adding cotton rope, sisal and even calcium Parrot perches to the mix to provide alternatives in softness or abrasiveness.
The softness of the cotton rope might provide your parrot a comfortable place to perch and sleep after a long day standing and playing on hard wood, and a mineral perch offers him a way to rub his beak and claws to keep things in trim.
Other perches come in the form of a swing, or even a perch tent. ET spends a lot of time swinging on his his swing, which is good exercise, and Priscilla my Umbrella Cockatoo loves to snuggle in the perch tent.
What I know for sure, after many years of keeping pet parrots, a wide variety in Bird Perching options is essential to having a happy and healthy parrot.