The eagles Parham photographed no doubt brought the Red-tail to their nest intending not to raise it, but to feed it to their own nestling. However, when it was deposited into the aerie, the hungry and disoriented fledgling immediately began begging for food alongside the eaglets. The confused parent eagles mistook the hawk as one of their own and began treating it in kind. Though surprising, such behavior can occur when the wrong species ends up in a nest. That’s because most adult birds cannot recognize their own chicks from others—a vulnerability that brood parasites exploit by laying eggs in other species’ nests.
I couldn't decide if the ending that happened was any better than the one that was originally intended by the eagles. The world is a harsh place.
As a tangentially related fact, I learned opossums have more babies than the mother can possibly feed, so many babies are doomed from the second they are born. Seems a cruel design quirk...