Hi there and
to the forums!
I'm so glad you were able to rescue Biscuit and Kiwi
It's great to have you with us, and you couldn't have come to a better place to learn even more about the best of budgie care!
FaeryBee has given great advice above. It's important to proceed at your budgies' pace to ensure you gain their trust. At this point in time, they are letting you know they are not quite comfortable with you so proceeding from that point on in the manner outlined above is the best way to help them trust in you
Also, you can let your budgies out of the cage when untamed as long as the room is budgie safe and you are comfortable with doing so. They will return to their cage on their own without you needing to catch them; if you choose to do this, know that it may take a while for them to return to their cage so don't do this if you have to leave the house soon.
Be sure to read through the forum's Budgie Articles and "stickies" (threads "stuck" to the top of each subforum for easy reference) to stay up to date on all aspects of budgie care. If you have any questions after reading through everything, be sure to ask as we'd love to help!
We look forward to seeing you around the forums!