Do Mockingbirds "Fly Over The Rainbow Bridge?"

Do Mockingbirds "Fly Over the Rainbow Bridge?" I often read or hear where someone's pet they loved was last seen "Crossing The Rainbow Bridge." I seldom get publicly emotional about an animal, though in my long years I have lost loyal dogs, birds, and even a beautiful silver miniature horse stallion that was still-born in my back yard.
I'd have to say the Texas Mockingbird is one of my favorite birds, mostly because of how closely I've observed them. We rehabilitated and released an injured Mockingbird youngster we found in our yard a number of years ago. The next year he returned to our feeders and hung around the yard, and then the next year a pair nested in a short bushy tree in our front yard.
There was no proof, of course, that it was him, except possibly that he stayed so near and appeared to trust us when we went to the car or mailbox, or to shoo away the neighbor's cats when he'd strafe them.
We'd see him each spring for several days in the top of a particular tree in our back yard. He'd fly up several feet, hover, then alight back in the tree. It looked like he was flopping back down, and the tree leaves appeared as if he were compressing them.
We had to conclude this was his mating performance because within a few days they'd build another nest in the same tree in our front yard. Luckily the tree got taller and bushier each year. We'd long since stopped feeding any of the birds because of the neighbor's cats and we had even considered deterring the pair from nesting here.
They had mixed success for a number of years. We ran the cats off whenever we saw them near the front yard, he'd strafe them, and I think most of the fledglings survived. This last spring he may have slowed with age. One of the cats left his wings on my front porch. Do Mockingbirds "Fly Over the Rainbow Bridge?" I don't know, but I miss that little guy! Cat owners, please keep your pets indoors!