Wyvern trouble!

Did Wyverns in Cloakwood get a boost or what? I have played in BG1, TuTu and BGT and never remember them being so tough. It's like they are on steroids, they hit so fast and so easily and so hard, even without their poison they kill anyone fast. Jaheira and Khalid, equipped with full plate mails, shields+1 and ring of the princes get torn apart rapidly. And Coran misses to hit them with his bow occasionaly, so they have good AC as well. They resist blindness and even a super powerful wand of paralysation too! Threw a fireball and they all saved and took only 'barely injured' before they killed my tanks with glee. What happened?

I can try to kill them with my Shadowdancer by using HiPS but even with +4 to hit bonus from backstab, my guy can't hit them reliably, their AC is good. And if he fails a single hide in shadows roll they can eat him alive fast! (And I would miss him terribly! :p)

The wyvern cave in Cloakwood is particularly difficult, it is a very narrow area and wyverns can just one hit KO my mage. (who had a meager 20 hit points, all gone in one hit!)

Do you have any ideas to help? I don't have monster summoning wand/spells. Also, do wyvern claws do crushing or piercing damage? From the 'thunk' sound when they connect with Jaheira's full plate I think they use crushing so a potion of absorbtion and girdle of bluntness can help? It is not poison that is trouble, I have tons of antidotes. They just right out rip my characters apart with brute strength. :'(