ZEROS Fauna - the T.rex-Bird

On Zeros, there is a rather special group of birds that did not follow the same evolution as our birds, following the extinction of the dinosaurs at the end of the Cretaceous. These primitive birds bear the name "dinornid" because of their strong evolutionary resemblance to the famous Dinosaurs!
This group of landbirds has derived in multiple variations, adapting in various ways to the ecosystems of Zeros.
Among the Dinornids, there is one that is particularly imposing: the Gorgornis imperator!
Its name derives from ancient Greek: γοργός / gorgós (“fierce”, “terrible”) and ὄρνις / ornis (“bird”). The species name imperator means "emperor".
These giant birds measure 2.50 meters at the shoulder, and almost 5 meters in length. There is no big size difference between males and females. Female Gorgornis are more slender than males, exhibiting more neutral colors. As for the males, they are easily recognizable by the many wattles that hang from their featherless neck.
Distribution: The species lives on the Madura-Dala continent, mainly on the North-East part, but the species has already been observed in the western regions, but with darker colors (probably a subspecies) .
Morphology: This dinornid has rickety wings, devoid of claws. Its hind legs are very muscular, like the Cretaceous T.rex. Its horny beak resembles a massive version of the beak of the Phorusrhacidae, additionally wearing a hollow helmet, like the hornbills.
Ethology: Gorgornis imperator is a purely carnivorous predator that hunts large prey, such as deer, in groups. It is one of the few Dinornids to have a hypercarnivorous diet, as even its closest cousins have an omnivorous diet. The breeding display takes place during the dry season. During this period, males search for females by calling each other vocally through their territories. If 2 males compete for a female, the confrontation is first done by intimidation, by exposing their wattles and helmet. If that's not enough, they engage in a fight with beaks and paws. These fights are violent but rarely fatal.
Reproduction: The female lays 2 to 5 eggs in a nest each year. She makes it by digging the ground and, after laying her eggs, covers it with plant debris. She fiercely protects her offspring and teaches them to survive after hatching until they reach maturity.