Sounds like we have a couple ole grey whiskers still chasing ole Wiley.
The Herter's caller - I didn't start attending Keggers until college and back then we had big arse speakers blaring, not a tinny Herter's. Our family purchased the ole Herter's record player with the huge green metal speaker and green box record player when I was in HS, probably '59 or '60. Took D cell batteries and 45 records.
We had records of dying rabbits, mice, crows etc - whatever Herter's had - we had, like paper mashie(sp) crows and a horned owl and every 45 record they sold. My brother and I practiced duck calling off those records with Herter's wooden hand held duck and goose calls and more often than not, we became good enough that we could turn small flocks all the way down to a couple ducks - a mile away for at least a fly over to check out our decoys. We thought we were pro's.
Problem was the huge speaker had to be connected with a short 4' cord to the record player. Had to place that needle on that 45 record just right, lower the lid and run like h*ll to our hide before the squealing started - of course, the old 45 record was scratching before start-up. 1st year probably killed 30/40 fox but just a couple coyote - that was in SW Minnesota area.
Crows - the fighting crow 45 record would bring in crows from the next county - they always sent a scout or two - if you didn't kill them on the 1st pass - the flock would sit off a ways and raise cain but wouldn't come in. Kill the scout and you had dozens of crows dive bombing that horned owl with fake crows around him. We normally could get off 4 to 6 rounds per person per flock, as we had plugged shotguns (3 rounds) and had to reload from our pockets.
Then we moved up to the Johnny Stewart tapes - easier but not much better than the old 45 records as far as fox/coyote coming to the sound. Shot the largest male coyote of my life in Nebraska using the Stewart tape of a dying rabbit with that ole Herter's speaker - Silver colored and probably weighed 50+ pounds - my buddy mounted it, as I couldn't afford to do it.
I guess predators weren't quite as smart back then as my recorded sounds from my e-caller sound so good to my ears today that it's like ringing the dinner bell and every predator in the area should come a running - but they don't - except the young dummies'. I'm thinking I should try a prairie dog distress sound in the dead of winter??? Can't hurt.