Eyes like a hawk - Friday's facts, fascinations and folklore

Several times this week we had a red-tailed hawk come perching on the vines near our house.  There is a nesting pair in the woods nearby but normally we don't see the hawks perching near the house.

He looked quite majestic and I loved his yellow feet ( I wonder why they are yellow?).  And he got me thinking about the saying "eyes like a hawk".

A red-tailed hawk's eyes are nearly as large as a human's, although the bird may weigh only three pounds.  Such size results in a relatively large image cast upon the retina.  The retinas have a dense concentration of cones and a great many optic nerve fibers. The area of critical focus, known as the fovea, in the back of a hawk's eye has 1,000,000 visual cells or cones per square millimeter, compared to 200,000 in a human eye. Even more impressive, the hawk's eye has two foveas in the retina where the highest concentration of visual cones occur, while we have but one. Thus raptors can see eight times better than man and have an exceptional ability to judge distance.

If you hold a finger 2 feet in front of your face., you can see it clearly because you are focusing the image on your one fovea.  Now hold the finger 2 feet to the left of your head and move your eyes but not your head to see it.  It is not in focus because the light from it is not hitting the fovea.

For a red-tailed hawk with mutliple fovea, most of what they see is in focus.  So human's will never have eyesight as good as hawks!

As an aside, other birds - like seabirds and shorebirds have a ribbon-like fovea across the back of the eye in order to orient themselves better to the horizon.

Guess we are lucky we don't have to catch little creatures and birds to sustain ourselves.....


Here's a red-tailed hawk's call - Warning: it's pretty strident so don't play this is you are in the office and should be working!

National bird of Mexico - Friday's fascinations, facts and folklore

I'm sure everyone reading this knows what the national bird of the USA is - even if you don't live in the USA.....but how many of you know the national bird of Mexico???

No - I didn't either, until I looked it up.  As I am visiting Mexico this week, I thought I'd check into what birds I might see.  The national bird is the Crested Caracara and is used as their emblem. 

Photo by catmca

You can also see them in Florida, Texas and Arizona in the US, and then south into central and south America.

It is often known as the Mexican Eagle and is in fact a falcon that eats more like a vulture! They catch most of their prey by walking around fields and shallow wetlands, but sometimes they watch for prey from fence posts and trees and look for dead animals along roads.  They eat mostly grasshoppers and beetles, but other animals too, and eggs, fruit and seeds.   

A couple of interesting facts: Like vultures, they don't have feathers on their face as they would get matted and stuck with blood etc when they ate roadkill! 

Photo by Leppyone

You can see their crops showing in this photo

And my friend Colin just commented on Tuesday's post letting me know that the phrase being "fed up" with something originally was a falconry term.  If you gave your falcon too much food, it wouldn't need to fly and catch something for you, so it didn't bother.  It was fed up!  (Thanks Caulie!)

So do you know the national bird for any other countries?  What about:

• United Kingdom?
• Canada?
• Germany?

Please send your answers written with a feather, on a bit of roadkill - oh and mail it  to my Mexico address!