Tons and Tons of guys claim a crow is in effective, they hear it too much.. But I have the opposite luck.. I would say from after flydown until I quit 80 percent of the birds I strike are with a crow, maybe 20 percent gobble to a turkey call when they didnt gobble to a crow, which I turn to second..
I will say this, I have only found two readily available crow calls that work with a great deal of effectiveness. It is about VOLUME and pitch.. I prefer a touch higher pitch than a crow and alot louder...
A effective crow call when running and gunning is a tool I will not leave the house with, it is a huge advantage to have a bird gobble without having to use a turkey call. .
As for owl, they are primarily used in the morning.. Alot of days it doesnt take alot to get a bird to sound off on the roost..