Fantasy Animals - Roc Bird
Although primarily carnivorous, the gigantic Roc bird is known for its frugivorous diet and was commonly spotted pecking pineapple-melons. The short yet extremely powerful hooked raptorial beak is suitable not only for ripping flesh but also perfectly designed to mash some ground hefty berries. Nonetheless, the Roc bird remains the biggest flying predatory organism in Oominor with a wingspan about 45 – 65 feet long.
This prey bird hunts large animals attacking them from the air piercing the head of the creature with sharp hooked claws, with all its weight, the bird falls on the head of the animal and presses it down with the ground. Frequently the prey dies instantly without realizing what has happened.
Atop the head of the Roc is crowned by long feathers that fan into a bold crest when the bird feels threatened or during the fights with other representatives of the same species.
The Rocs hatch from enormous ground-colored eggs. All chicks possess some sort of a small horn aiding them to chip open the hard shell of the egg; however, later the horn reduces I size and completely vanishes before the baby Roc learns how to fly.
Roc birds prefer open spaces and large canyons where they hunt their favorite mammals: behemoth, elephant gopher, and boar-mammoth.
How could fly?
I think that physics does not work exactly like that, there is a specific range in which the gravitational acceleration allows flight and even if it were so, this has more to do with the take off from the ground of the bird and the lift when flying, It is practically a bird, it could not take off again if it lands because its legs and wings would not have enough strength to lift it
Well, I really appreciate your comment! I'm not quite good at physics, unfortunately, but I’ll with arms open accept proposals you have in mind regarding how such a giant animal can fly 
As I said before, I'm still working on my world fixing things that are halted, and comments like yours truly help me. Thank you so much!!!
Thats good, well I always liked giant birds pterosaur sized, the principal difference that make this two species different is that pterosaurs used their four limbs for throw themsleves to their, in something like a pole vault. So I dont really know how this can be solved, because this bird practically have a phorushacidae (terror bird) size, so to fly is requiered excesive energy or some external support. So, for that I dont really how you could solve it.
These İntroductions and Profiles are simply delightful as well as well made 
Thank you!
Your works are absolutely creative, you are very welcome
Now that is one impressing bird. Would most certainly not be surprised to see them attacking humans and other of the sentient species around - humans are, after all, a pretty decent size for a snack. Should be easy to carry them to the nest too...
Although, knowing humans, I presume the birds who did this soon ceased to exist, basically breeding a population of rocs that would leave humans alone. I presume some younger birds might cause problems from time to time, though.
Love the drawing of the chick too - they look... some mix between ugly and cute, and that's exactly how young birds look 
Would be interesting to know how large they are, compared to humans. Also, I presume rocs nest on cliffs and such? I have difficulties imagining trees large enough to take the weight of a roc nest (certainly not if they build in the same style as eagles and ospreys, who make heavy nests and are... quite a bit smaller). Cliffs should keep the chicks safer from predators while sustaining the weight.
Do younger birds have a slightly different plumage too? Looking at the eagles here (and their close cousin the American bald eagle) it takes some 4-5 years until the plumage is fully in "adult" version. The younger birds have a more spotted appearance, and have a darker tail and head than the adults.
Also, I presume the females are larger, as is common with eagles and other larger raptors?
Love the idea of the feather crest, by the way 
Makes it easier for the bird to communicate. I presume they also show off their wings and fluff up when they feel threatened, like some owls do when defensive. It would also be fun if they had this flying courtship similar to bald eagles - it would make for quite a show!
And I love how much information you have fitted in the sheet here again 
Excellent work, as usual.
Thank you so much 😊 I’m honored.
I definitely needed to add the different plumage coloration on various age types... but I will try do it next time I’ll have a bird or reptile.
I think they do lay eggs on the cliffs closer to the ground... I can’t imagine a tree to support their ginormous trees. Though there are definitely big odd trees growing in Oominor... hmm... need to try to draw plant life of my world one day.
Thank you again for your help!
P.S. Wondering when you’ll be free for the commission 
Would be awesome to see plant life too!
And my commissions are open - but I'm working on another commission right now, so you'd have to wait a little while before I get started. Still, that's no reason to not discuss any details or such
I’m not in a hurry XD
Then I’ll send the details tomorrow through notes if that’s acceptable.
Sounds great!
XD
Could I draw my own artwork of them?
Don’t see why not. Just please link my art
Thanks, of course. Man and ARK dossier of these guys would be awesome.
That is one gigantic bird. One question however, was the height of this Roc based off that of the Giant New Zealand Moa? Looking at it, it looks to stand 3.5 meters/11.5 feet tall which would make it about as tall as that extinct bird.
Kinda, well... I thought of using flightless giant bird for the Roc but then I then I just changed my mind, made it more classic.
Um... okay, I just wanted to ask because the Roc was based off the extinct Elephant Bird and it stood 3 meters/10 feet tall. I wasn't sure if that was the height you were going for or you intentionally made it taller.
Thank you for your interest!
You're welcome
Beautiful!