Are Blue Jays descendants of dinosaurs?

Yes, Blue Jays, like all modern birds, are considered descendants of theropod dinosaurs. This connection is supported by extensive fossil evidence and studies in evolutionary Biology that trace the lineage of birds back to small, feathered dinosaurs. Therefore, while Blue Jays themselves are not direct descendants of the large dinosaurs we often think of, they are part of the avian lineage that evolved from them.