covering the suffering bird with flowers does nothing, it doesn't heal the poor thing, it doesn't help. the stick tortures the feathered creature and shows no empathy to the suffering it faces. without the option to help in any other way, the only option of Compassion, is to kill the bird without torture with the stone, instant, painless, quick. because you couldn't help the bird to keep it alive you have to take the second route, the one more brutal but understandable. yes, life is harsh, but at least death is effortless, a quick snap, a gunshot, a stone falling from meters above. yes, the bird is dead, but at least its not in pain anymore, the flowers would have done nothing but make suffering look pretty.
I killed the bird with the stone then covered it in flowers, because yes it's dead but the flowers can live off of the bird, and so yes a life has been lost but more granted, besides, its in our nature to make death look beautiful.