Are you sure that's the "cross"? Browns are trout and specs/brooks are chars. Lot of genetic differences there for hybridization. Not challenging, just curious. Love to see docs on that.
I fished pretty much every foot of every trout stream in N GA and never caught or saw a "Tiger" trout. Not saying they don't exist, just always thought them a folklore myth. I was no slouch at catching trout either. Wasn't any big thing to trifecta a good stream back when I was a kid. Browns were the hardest to find back then, specs were everywhere there was fast water. I always targeted the hold-overs and stream born, just because (as mentioned above), they were much very colorful and better tasting for sure.
Yep, they're a brown/brook hybrid. Different genus, but they're closely enough related to produce offspring. And they both spawn in the fall at about the same time. I have caught a couple of the stocked versions, and know a couple of folks who have caught wild ones. The wild ones are extremely rare.