Date: 1/31/18 10:52 pm
From: Nathaniel Wander <nw105...>
Subject: [obol] So-called 'bird's-eye views"
Bird's fields of vision are so various and so universally different from our own that, to borrow from the JBS Haldane quote, "they are not only stranger than we imagine but stranger than we can imagine."
Humans have overlapping, forward facing binocular fields of 1200, while various bird species' binocular overlap generally falls between 15 & 300--but owls have almost 5000.  (And some birds have a gap in their forward vision where it is block by their bill.)  Our forward facing eyes give us a total field of view of perhaps 1800, but, depending on how far back their eyes are set, birds' may reach almost 3000, the major part, of course, monocular.  Also, depending on where their eyes are set, birds generally see a great deal more above and below their faces than we can.  Indeed, some, like woodcocks, have eyes set so high on their heads they can see behind themselves.
For anyone interested, a wonderful book by Graham Martin came out of Oxford last year--it's titled The Sensory Ecology of Birds.  Sensory ecology is a brilliant, 'relatively' new science.
Nathaniel WanderPortland, OR
Max Planck is supposed to have said: A new scientific truth does not triumph by convincing its opponents and        making them see the light, but rather because its opponents eventually die        and a new generation grows up that is familiar with it.Andreas Wagner observed of Planck's remark: Science, like nature, advances one funeral at a time.  (Arrival of the Fittest, p.197)

On Wednesday, January 31, 2018, 10:07:29 PM PST, <obol...> <obol...> wrote: Msg: #6 in digest
Date: Wed, 31 Jan 2018 16:11:41 -0800
Subject: [obol] Re: Boardman/Morrow county Corvid behavior
From: "Wayne Hoffman" <whoffman...>

Hi - 
When I am observing birds I often have at least some idea of what they are up to, but with Ravens I often do not even have a clue.

In general (there are exceptions) birds eye anatomy is such that they have some binocular vision, but their highest-resolution vision is one eye at a time, so when bird turns its head sideways it is often to look with one eye at something high overhead,or at something below it. I have learned to see where the bird's upper eye is "pointing" and have often seen high-flying raptors they are watching, and that otherwise I would have totally missed.  Other times the thing they are watching is an airliner, far above patchy clouds.  The Raven could have been doing something similar, but this also could have been part of some social interaction with other Ravens that might not have even been visible to you.  

Wayne
On 1/31/2018 3:41:51 PM, Pete Szasz <paszasz...> wrote:
These guys are always doing interesting stuff but never seen one turn there head all the way around in that manner?
 
Join us on Facebook!