Hi Everyone...I am new here but seems like a great group!

This is the first time I have grown sunflowers. 3 weeks ago I was pretty happy...I had planted a bunch of seeds against the south facing wall of my house. They were starting to push up and then...they disappeared! After close examination, it looked like either the little black/white birds in my yard or crows. I was heartbroken! I went and bought more seed, planted a bunch in the house and a few outside.

Question, how soon can I put my plants outside without getting "attacked"? I put clear plastic cups around the ones that were sprouting outside, to protect them but how long before they should be safe?