Proto-IE: *swAlw-
Meaning: a k. of small bird (nightingale, swallow)
Russ. meaning: птица (соловей/ласточка)
References: WP II 535
Comments: The association of a fish and a bird is questionable, but not impossible. For Slav. s = Balt. š < *sw- cf. *swel-men- > Gr. sélma = Germ. selm- = Slav. *selmę = Lit. šelmuõ etc.