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chirp

Even during WWII, radars were sending microsecond-wide multi-megawatt transmit pulses. In subsequent years, radars hit the wall on transmit power from reasonably-sized antennas. They would arc the waveguides and plasma the air in front of the antenna. Wider pulses lost range resolution.

So they invented chirp radar around 1965, a wide pulse that sweeps frequency during the pulse. At receive time, it can be processed to reconstruct a narrow pulse and restore range resolution.

I thought of this while feeding my scrub jays breakfast on the deck. Birds chirp; must have copied the concept from radar. I suspect that a distinct time:frequency pattern distinguishes species and improves the detection s/n. So I have developed my own chirp whistle that the birds can learn to recognize from a distance, when I have their morning treats.

This morning one jay couldn't wait for me to distribute the treats onto the deck (mixed Fritos and Cheetos) so landed on my fingers and started eating out of my hand. Adorable. Then it bit my thumb for dessert.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard
Reply to
jlarkin
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It probably finally read the ingredients list and thought you were trying to poison it!

Fritos and Cheetos, part of a well balanced diet for birds?

You would be better off with seeds but bird seed can go bad, so perhaps better to plant flowers and let the birds feast on the insects said flowers attract.

John ;-#)#

Reply to
John Robertson

Fritos are their favorite by far. Ingredients are corn, corn oil, and salt.

I like them too.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard
Reply to
jlarkin

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Perhaps not too many Fritos for either you or the birds. Added fats and salt isn't good for any of us.

John :-#)#

Reply to
John Robertson

Bats use chirped signals for echolocation. Here is a sample:

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John

Reply to
jrwalliker

You'd die without fat and salt. Salt is a rare and valued nutrient in most places. Birds eat corn, which is why scarecrows were invented.

Isn't all food "added" ?

I assume my backyard birds know what treats they enjoy better than Melissa Mayntz does. Bird nutrition theories makes as much sense as people nutrition theories, namely not much.

Reply to
John Larkin

Did you know that copper is toxic to birds?

Had to backtrack on a birdhouse 'shingle' once - that I'd thought was a jim dandy idea at the time, for a wren box.

RL

Reply to
legg

Your heart is in the right place, but your head just can't listen to reason:

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Wild birds are wild - they need to survive in the wild (be it the city or not) on their natural diet, which they have spent millions of years evolving on. Humans can only interfere with that.

Reply to
Flyguy

That sounds mostly made up. A few Fritos won't hurt a bluejay.

It's just a bird anyhow.

There's nothing natural about San Francisco but the rocks. It was mostly sand dunes once. Nearly all the green stuff is non-native. I'm impressed by how many different kinds of birds thrive here.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard
Reply to
jlarkin

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