Are they nesting?

[Hypnotoad72]

I found one of the nest sites, a hollow coconut fiber tunnel, to be partly filled with millet strands, timothy hay, and even a few feathers.

It's cute how it's set up.

Apart from feeding time, there's, seemingly, always a finch in that little nest. On occasion, I've seen two.

I can't tell, due to the angle, if there are eggs in there or not and I don't want to disturb anything...

A pied male was in there before I swapped out the food dish.

They were 4~5 months old when I bought them, which was a month ago.

Of course, if I see the non-pied male go in there, then chances are there's no family being made... But I have heard territorial squabbles, particularly at night...

What other signs can I look for in potentially breeding birds? And is 6 months too young?

Thx!