
It's been over a month since I got this pair of cute finches. About 3 weeks ago, I noticed they're mating (or trying to... the male jumps on the female but is unable to stay that way for more than 2-3 seconds at a time). Was asking myself "when are they gonna make it?". Now, the time seems to have come.
Starting yesterday, I've noticed abnormal behaviour. She's jumping around, mumbling (not sure how else to put it?). He just sits, barely sings (he used to sing a lot). I wanted to film their behaviour, thinking there's something wrong with them. Boy was I wrong!
They seem to have succeeded at mating, as she is trying to build her nest. I started filming, and have uploaded the videos on YouTube.
Video #1
He's stationary, very quiet. She's moving around, "mumbling", while carrying a straw in her beek.
Notice the placement of the nest and its entrance.
Video #2
I've decided to move one of the sticks closer to the nest, so they can have better access to its entrance. Notice how the male and the female are trying to pull straws apart from the nest now (where earlier only SHE was doing this), only to drop them later.
Video 3
I installed the "thing" I filmed towards the end of the second video. Not sure how to call it, really.
You can see she's taking straws out of the "thing" and the nest's entrance.
Later on, she drops the straw. NOT in the nest

Video 4
I saw her grinding her beek (while holding a straw) against the cage and the stick she's sitting on. She then dropped it.
Then he was taking straws out of the nest (not the "thing"), and putting them down more carefully (he's "reaching" for the pile, not just drops it, you know).
And the pile of straws is just getting bigger. Is that where they're going to build their nest?!