Some guys yell, others use a whistle.
I don’t like to make noise. If the dogs can hear me so can the birds.
My setter runs with a collar. It’s a combo gps and e-collar. It has a tone function that emits a soft beep when pressed. Loud enough for him to hear but soft enough that only he hears it.
If he’s heading a direction I don’t want him to I can turn him around with that tone. It works awesome.