Have my robins left their nest?

Hi all, 

I’ve had a pair of robins busy building a nest in my ivy over the last week, when I was out refilling the bird feeder Friday evening one of them came flying out and spent quite some time flirting between the fence and a bush near their nest. I saw one of them Saturday morning at the feeder but since then haven’t seen either. 

The feeder is still being used as we’ve just had to refill it but no sign of our friends since Saturday AM & the other half said he’s not seen them going in & out of where they have built the nest. 

Is it possible they’ve decided to move on? We want to check the nest in case there are eggs but don’t want to disturb it if they’re likely to come back. We’re new to this but hoping we’ve not upset our newest residents already!