You take the feather to a guard in OT and tell him I am here to make p. Then tickle his **** till he pees in his panties and you will get xp and 5 coppers
I really enjoyed hunting these guys at 20th. I would get nearly a full blue bubble with each kill (at the "dangerous" con level), but they would almost always bring me down to 1-2 bubbles of health including a use a mend for a 25% healing. They can hit for up to 40 and stun as well, but are not social. They also run when down on health. In fact the only things to look out for in this area are the Sarnak (flunkies and conscripts). Everything else will leave you alone.
You can get beaks off them which I can sell for 1pp 5gp (as an lizard who is amiable in Cabilis). Unfortunately they do not stack.
Recently a merchant has showed up near the pond, who, while being a lizard, is indifferent to everyone. Selling to her I get about 9gp, however often the convienience is worth the loss of gold since it can take 15min just to get to Cabilis.
Very rarely they will drop gems (so far topaz and pearls) worth over 3pp to an amiable vendor with base lizard PC charisma.
Besides the Lime Plumes, they will also drop normal feathers which are not worth that much...a few silver I think.
Kwinn the Outlander requires this item among others for his quest that rewards an Iksar Metal Tail which as far as I know nobody knows a use for yet. Just a little fyi.
Kwinn btw is a very rare spawn in Firiona Vie and Iksar Monks need badly to kill him and return his head to their guildmaster for their shackles.
I have this too since when I was 18 I killed several and got that feather... and a beak and 2 pearls. But I even asked Guides and GMs NO ONE has known as of yet.