A swifts timing

The young birds are getting some fuzzy feathers. At this time both parents can go out to hunt for food. The young will be more often allone on the nest at daytime.

Swifts lay their eggs with intervals of about 24 to 30 hours. as long as there are more eggs to come, they won't hatch their eggs. So at the time a parent is on the nest for a longer stay, the hatching is started. This way the egg's will come out at more or less the same time. And after 42 days the young will leave the nest together. Mum and Dad will then stay at night at the nest for several days before they also leave for Africa.
We once had a 'late' chick that was born a few days after the others. That one left the nest a few days later than it's brothers and sisters. But for now I'm rather sure that their is no third egg or young.