I'm genuinely not sure about this one, so be honest. SIL lives several hundred miles away, and decided that she would keep DD's birthday presents until she next sees us, rather than posting them. We have no plans for a visit, so this will probably be in a few months' time at least. The same thing happened at Christmas; SIL had presents bought and wrapped but never managed to get to the Post Office, so she brought them with her when she finally visited, in February.
Also, DH's parents (also SIL's parents) visited her and then us the other week, so they could easily have brought the presents down with them. I suppose SIL just wants to be there when DD opens them, but AIBU and ungrateful to think that giving presents several months late is just not quite right? I think she should have just posted them. She didn't send a card either (and while I think cards are a waste of money, the principle sort of bugs me). It was DD's first birthday, if that makes any difference.