July 12, I caught these in the afternoon and thought I should spare you of too many messages in one day.
I was struck by how she looked at me.
Robins use sight to catch worms. Because their eyes are on the side of the head, they must tilt the head to see objects directly in front of them. They do not use their sense of smell — like other birds. Robins have a terrible sense of smell. Experiments have ruled out the possibilities that robins feel vibrations that worms make, or that robins hear worms moving as Woodcocks do (1) .They seem to have average eyesight. Because robins feed on worms which move very slightly, the robin needs a slightly larger fovea than say, a goldfinch which eats just seeds. http://www.
A bird's retina actually has three types of photoreceptors that "translate" light into nervous impulses:
- rods - black & white vision in dim light
- cones - color vision in bright light
- double cones - color vision
The interesting thing here is that humans only have two types of photoreceptors, rods and cones. .... Moreover, bird retinas, in contrast to human retinas, contain no blood vessels. This prevents shadows and light scattering, which cut down on human vision. http://www.
*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~
July 13 2016
The white crescents that we noticed over the eyes yesterday are taking more shape today
Notice the youngest one (at the back) is just starting to develop the white plumage above its eye. The downy ear tufts that were on all heads yesterday are completely gone now on the first hatched.
(1) Woodcocks have a back and forth rocking motion on the ground that is really fun to see. I watched one last year.
"The vibrations from this motion may prompt earthworms to move underground, making slight sounds that the woodcock may be able to hear or feel." https://www.