Jovians have nictitating membranes (see here) because they live in wind and rain (see here).
Yhtrians have nictitatng membranes because they fly (see here) and are at home in the weather (see here).
The Aleriona also have them.
Previous posts about "going bird":
Spirits Of The Air II
No new posts on this blog until tomorrow but meanwhile see NGC 5457 on a companion blog.