I saw the film “Take Shelter” last night, which includes one of my favorite things in the world: the strange shifting shape of a flock of flying birds. I’ve been told that these patterns come partly from most bird’s ability to see 360º around itself. The other reason must come from some desire to stay tethered to the group, which looks like such an elaborate movement that usually translate into the short distance of moving from one tree to the next.
The film was a beautiful meditation on the senses and what is “seen” versus what is happening. Without trying to give too much away, Curtis’ visions and hallucinations belie his rural Ohio existence but hint at either an apocalyptic shift or a deep retreat into the mind. Perception is always subjective. If seemingly important messages are sent to us via senses or modes not normal culturally, how can we say if we should follow them?  The film used the image of a flock of birds as a metaphor for the uncanny, how this nameless pattern might express a deeper strangeness about the world. Like an augur, we hope to “read” the communications that animals can’t speak explicitly.
On reading more about birds, this may have some value: birds have the largest eyes relative to their size of any mammal, with a flattened shape and ciliary muscles that can change the shape of the lens rapidly. They have four color receptors (most mammals have two), allowing them to see not only the ultraviolet spectrum, but magnetic fields. The ratio of photo receptors to optic nerves is very high, giving them greater visual acuity. Humans have 200,000 receptors per square mm; buzzards have 1,000,000.
Birds can also resolve movement faster than humans, due to their perception of flickering rate. Any movements above 50Hz appears as continuous to humans; for some birds, the threshold is more than 100Hz without seeing this as a blur. Amazingly, birds can also perceive incredibly slow movement that we also do not actively see, such as the passing of the sun through the sky. We tend to project our knowledge of the world on others, with the assumption that there is at least a universal perception of it. The divide in perceptions of the world points to an interesting ontological argument.
I realized I actually posted about this last year, so here is the video again…