The alpacas are nice but not very trusting. I still can't get too close to them without them darting off.
The llamas are quite friendly, actually. About the same temperament as the alpacas. The biggest llama, Dolly, is the mother of Serendipity, who is only just over a month old, and so Dolly is quite protective of him. But she is never nasty - she just doesn't let him out of her sight, and is very guarded when it comes to us being around him.
I find it kind of fascinating that llamas and alpacas have quite a bit of control over when they will give birth. Rather than having a set due date, it will be a period of about 30-45 days in which they could give birth at any time.
They never give birth at night, and very rarely give birth when it is raining. They will wait for a day when the weather conditions are pleasant.
The birthing process also appears to be relatively painless. They give birth standing up, and show no signs of distress. You can turn your back for 5 minutes, then turn back around and suddenly there's another alpaca/llama in the pen.

