Slavic water birds

From: João S. Lopes Filho
Message: 11158
Date: 2001-11-16

What's the etymology of these names of aquatic birds
Russian tsaplia "heron" = Polish czapla = Czech c^ap "stork"
Czech volavka "heron"
Russian aist "stork"
Polish bocian "stork"
Russian c^aika "gull"
Czech rac^ek "gull"
Polish mewa "gull"   < *Germanic maihwa- ?
Russian lebed' "swan" = Czech labut' = SerboCroatina la"bu^d < *labo,ti <*albH-anHti "white duck" ?
Russian bekasa "snipe, woodcok" = Polish bekas "woodcock"
 
Any Baltic cognates for these words?