It has been said that the eyes are windows to the soul. Research has shown that the apertures of our eyes offer a glimpse into the mind. No doubt that this applies to human and non-human animals. The pupil response to cognitive and emotional events occurs on an even smaller scale than the light reflex, but with the right tools this response is measurable.
When we give a human or non-human being moral consideration, then this simply means that we take into account how they will be affected by our actions, omissions, attitudes and decisions. Sentient individuals, regardless of their species, have morally relevant interests in being alive and in not being harmed, and this does not vary according to the fact whether a species is rare or common.
This short videoclip shows a fascinating encounter between a rather naughty and very persistent hooded crow and a juvenile mute swan. Neither the victim nor a nearby adult bird, presumably a parent of the young swan, seem to be too much annoyed by the antics of the crow, who repeatedly pulls the tail or tries to get hold of some wing feathers.
The most common causes in the wild for birds loosing a leg is entanglement with thread, fishing line, balloon ribbons or other litter. This can happen at all ages, even as a nestling. Other causes include predator attacks, birth deformities or injuries caused by traps and snares.
It is nesting season and corvid fledglings are about to leave their nests to start the big adventure of life. Corvid fledglings are fully feathered and healthy looking birds, who can perch, stand and hop by themselves. They are already able to fly short distances. Fledglings of many bird species leave the nest at this stage, and for good reasons. If they would remain in the nest, predators could have an easy meal, killing the whole brood at once. Leaving the nest and hiding scattered in trees, in the undergrowth or in bushes, even when not fully developed and not being able to fly properly, is the best way to increase survival chances. It gives fledglings the time and required exercise to improve their flying skills, which often takes less than a week of daily practice, after they have left the nest.