A bunch, if you don't mind! Your post delves deeply into a personal pool of questions within me, all of a vein similar to the facts you wrote. IMO, I think the word "cruel" is less descriptive of nature than "ruthless". We watch large numbers of Gambel's Quail here daily, feeding them seed every morning. Their babies are the cutest thing to observe, running along with their momma and papa, who usually stands and watches for trouble. We do not know if the young are fed in the nest at all, as some we've seen running about have bodies only slightly larger than golf balls. These birds can fly prodigiously, but seem to prefer not to except in time of emergency. They are undoubtedly easy fodder for the large flying predatory birds. Yesterday my wife "ran off" a malingering cat, which no doubt would devour a bird, could it catch one.

Male Gambel's Quail in
Joshua Tree National Park
Of all places to call home, this bleak desert is a curious place to imagine as home for these quail, but surprisingly, they are classed as desert dwellers. The quail we had in Missouri were definitely another kind, much more prone to flight. People (?) eat quail, as a delicacy!
Children becoming aware of their mortality is a fact of life, no? I always say, despite the strong survival instinct present in animal species of all kinds, none except the human, are aware of the inevitability of eventual death. That awareness among us makes for a philosophical outlook upon which may be built hypotheses about why humans wage war, kill lesser species for "sport" (?!), attempt foolhardy pursuits which can result in death, commit suicide. I cannot think of any living thing other than humans that commits purposeful suicide.
Regarding preying upon the lesser-strong, a parallel exists in human history where political "leaders", Joseph Stalin, for example, strengthened his society by destroying foodstuffs rather than allowing it's distribution, thereby creating intended famine. This "cleansed" his country of those most susceptible (and least productive): the aged, the sick, the already impoverished, succumbed first, leaving the strong (and therefore the most productive) alive. Estimated numbers dead run from 20 to 40 million! A perverse face of "nature"? imp