Aussie Finch Forum

Im just going by the pair of blue faced parrot finches I have. The amount of the nest material used would be a really good insulator, both the blue faced and the red throated parrot finches have built really thick nests. My blue headed pair hatched out two babies on 11th May this year.
Temps in Adelaide for May were average 19C daytime and 10C but there was a couple of nights with 6C wet and very windy.
The young seem to be doing well. The aviary is placed with the back to the prevailing weather, nest was a wooden box, located high.

had a look this morning and they have hatched

Not sure how many there are, the nest box is packed to the roof and can barely see in. It is also high up in a wooden nest box similar to what you have described Diane.
The temperature is only getting down to around 10 so hopefully they will be fine.

I have young tri-colours in the nest that are about 16 days old and last night the outside temperature got down to -1°C. The temperature inside their aviary at 7am was 10°C and they are still alive. As long as your aviary is well protected from winds, I would think they should be ok.