The mockers are extremely territorial, so I’m surprised at the amounts and varieties of birds in your back yard. But it will be interesting to find out of the mockers prevail or if the jays get to move into a new neighborhood.
In our subdivision most sections of 2-3 houses in a row have either mockers or blue jays resident, but not both. During nesting season, the mockers chase all the other birds away a couple times a day, as well as harassing the people and the cats!
This appears to be a takeover attempt by the jays, but it’s too early to see whether it’s just the food access - of which we have plenty for all! - or whether they’ll try to nest.
Nature, you know? Always something new!