Varmint calling decoys, do they work??

[Armored farmer]

I have read that natives used a single feather hung on a limb by a thread or horsehair.
It would dance 0n 5he slightest breeze and act as an attraction.

 

[.308 Norma]

I kinda like to have the birds circling around, as I believe they add a 3rd dimension to the illusion we try to convey with our prey distress sounds.

Yeppers, that's what I think too. It seems to me like a bunch of squawking magpies hanging around couldn't do anything but help add to the "illusion" that there's something dead or dying there.
How big are those cara cara (Mexican eagles) anyway? I can't tell from the pictures.
I used to black bear hunt up in Salmon River country with a buddy that swore by his predator (dying rabbit) call. We never got one, but apparently my buddy had had luck calling in black bears in the past.
I remember that he insisted we sit back-to-back when he was calling because he said he was once by himself, calling, when he heard something behind him. I guess he turned around just in time to see a good sized black bear, not 10 feet away, spin, and take off clawing his way up the hill as fast as he could go. My buddy said it all happened so fast he never even got a shot.

 

[hps1]

If I had to guess, I'd have guessed a tad less than listing in Wilkipedia, but here's what they say:

It has a total length of 50–65 cm (20–26 in) and a wingspan of 120–132 cm (47–52 in). Weight is 0.9-1.6 kg (2-3.5 lbs), averaging 1,348 g (2.972 lb) in 7 birds from Tierra del Fuego.[

https://en.wikipedia.org/wiki/Crested_caracara

They make a distinct noise when feeding, which I was never able to quite duplicate on any of my calls so I placed a small tape recorder near the carcass in first picture above and captured some of their vocalizations. It was a good idea, but never produced, like some of my other endeavors.

Regards,
hps