Magpie nest

Hi there, I’m completely new here, but wanted to ask a question. Next to my work at a shopping centre there has always been a nest of magpies. We often see baby ones every year since we start so early in the morning. Do magpies abandon the nest? I’ve just turned up to work this morning and seen mum and dad magpie around the car park (not usual) but I’ve noticed that the nest has now gone (centre staff are  cleaning the roof where they were settled. Just wondering if they leave at this time of year and that’s why it’s been removed? Or perhaps staff have done so forcing them out?

thankyou for any help, just a little concerned as we’ve been very observant of the family this year and a little baby was attacked by crows Cry