Those are the network time protocol (NTP) looking for time servers. Take a look at /etc/ntp.conf – that sets up the configuration for NTP on your system.
The ntp.conf file selects a number of servers from different server pools.
If you want, you can trim that down to four or so.
To see how it’s doing, from the command line, type:
$ ntpq -p
That will show you the time servers you’re connected to, and status. Very low bandwidth, a few kb per minute.
Sorry, I was wrong about this - it turns out this is unrelated to PiAware. In my case it’s actually the FR24feed software running on the same Pi that is constantly hitting those NTP servers. So it seems that FR24feed ignores /etc/ntp.conf and goes it itself with it’s own NTP implementation. Nothing to do with the PiAware software.