I saw the first worker wasp of the season. She was hovering near Colony 1.
Earlier this season we saw a lot of Queen wasps. This suggests that it may be a waspy year. There have also been lots of aphids for the wasps to feed on. Wasps require mostly protein early in the seasons which they use to feed their brood. They switch increasingly to needing sugar during the season, which is why they try to rob honey bee colonies.
I have annual problems with wasps. These are most noticeable in central Oxford. I've seen wasps trying to rob my hives at dawn (6am), at dusk (10pm) and all through the day. This continual onslaught would destroy a weak colony so I stop down the doorways to a space about 9mm by 25mm. Even so the wasps still get in and may even be attacking the bees through the Varroa screen under the hive. It's brutal.