why do i hear lovebirds wings flapping in my nest box at night are they mating?

No they will not be mating ,Love birds do not mate in the dark, something may have disturbed them and caused them to wake up and flap .

The slightest sound will disturb most birds at night as this is when they feel most vulnerable.

They only mate in the daylight as their mating ritual involves them seeing each other.

When they do mate it is usually 6-8 days after that the hen lays.

When lovebirds mate, they naturally flap their wings for a number of reasons. In the males, it helps the flow of semen through the penis and into the female. In females, it helps them absorb the sperm and start the process of fertilizing her eggs.

Flapping wings is a good sign, and you should be expecting little baby lovebirds within a month.

Be careful however, because lovebirds can be very shy, and dont like people watching them when they get down with each other.