kos, kossyphos, etymology, and another birds

From: João Simões Lopes Filho
Message: 19240
Date: 2003-02-25

1) Is there any link between Czech kos "ouzel, merle", Greek kotyphos/kosyphos "ouzel" and Greek ksouthos "species of bird".
 
Francisco R. Adrados states kos (kosU) < *kopsos, but give no other cognate to confirm this statement.
 
2) Any link between Latin sitta "Sitta europaea"  and Greek aisakos "species of bird"? I tried aisakos < *a-sity-akos.
 
3) And *kig^H ?  Greek kikhlos , Polish czyz, Russian c^iz^, Czech c^iz^ik.
 
Joao SL