I used to think that Blue Jay young were the biggest Big Babies! They dwarf other young birds like the chickadees and nuthatches, coming out of the nest big and noisy and so needy!
But this summer, I've had a family of Common Grackles in the yard, and their big whiny young are the new winners of my Big Baby Award!
They follow their parents around begging for food and crying and crying and crying. The high-pitched squawking can go on for 10 minutes at a time. The parents ignore them, as if saying "if you're big enough to follow me around like this, you're big enough to get your own food! Now bug off, junior!"