The last couple years I had Bluebirds nesting in snags in the back yard (both snags have since fallen over). I cut way down on the food in the feeders, which I usually do anyway in the summer, because I didn't want to attract House Sparrows. Would put out a little BOSS, but only put out the home-made suet nuggets if the Bluebirds wanted some. This Spring, I had a pair of Baltimore Orioles nesting in a large Pin Oak right above the feeders. Did the same thing, cut down on the food in the feeders, because the Orioles were very territorial about the tree. They were especially aggressive towards Blue Jays, Grackles, and Crows so I stopped throwing any tidbits on the ground (like old corn chips, which the Jays and Crows like). So I would favor the security of the nesting birds. During the summer and fall, there are normally abundant natural sources of food, so feeders are not critical. Birds eat a lot of insects and feed their young insects, so they are unlikely to starve if you aren't feeding them.

The blue jay population was hard-hit by the West Nile virus a few years ago and is just now starting to return to normal levels. That could be why you're seeing a greater number of jays now than in prior years. The fine folks at my local WBU gave me this suggestion for a similar problem I was having with starlings cleaning out my hopper feeder in search of peanut pieces. Put a screen across your feeder's opening. I used regular chicken wire having a 1" opening. Two overlapping offset layers may work better to reduce the opening to 1/2". This prevents birds from shoveling or raking seed out with their bills. The openings should be large enough to allow birds to pick out individual seeds. Chicken wire is easy to bend so I was able to mold it around my hopper's opening to keep it in place without having sharp edges endangering the birds.

I have a bird table/tray (platform on pole, screened to allow rain to pass through). In addition to a few seeds, I often put out (cut up) pieces of poultry skin and fat, fish skin, gristle, cartilage, fruit, older nuts and seeds, and sometimes bread. I have a baffle on the pole to keep rodents away. Sometimes I put out older butter or peanut butter. On the few occasions when I cook a ham or lamb, I freeze/save that fat (cut up) then later on make a melted, reconstituted "fat/suet block" that I put into a large hanging cage (in cold winter). The fat cage hangs from a tree about 40 feet from the house but in view of the window. The small birds can fit through the wire mesh, the woodpeckers can access the fat block from the outside of the cage. The jays can pick up what falls.

I would think so too, except there is definitely a light yellow tint there, similar to a canary. He/she really stands out among the flock of darker sparrows. I've never seen one like it.