"I see a bird in the sky now." or "I saw a bird in the sky now." or "I have seen a bird in the sky now" or "am seeing."
could you please tell me which one of these is correct.
thanking in anticipation
The use if "now" usually means you should use simple present, or in many cases (not this one) present progressive.
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.