It is judiciously, only when not banned at the birding site, and always within ethics guidelines published by National Audubon Society (https://www.audubon.org/news/how-use-birdcall-apps), American Birding Association (https://www.aba.org/aba-code-of-birding-ethics/), David Sibley, and other authoritative sources that I come across.
To illustrate, here is how I applied guidelines to get the shots on this page.
I do not use audio playback in heavily birded sites or lightly birded isolated locations where the practice is prohibited. These shots were taken on our property in the North GA mountains. We, and occasional invited guests, are the only birders. Sadly, we are only there a few times each year so it is lightly birded.
I do not try to call in uncommon or rare birds. We do occasionally get an eBird ‘rarity’ for NE GA. If I’m lucky enough to be there when they are and I know it because I hear or see them, I intentionally do not disturb them. To convince the eBird moderators, I will take notes and try to get a shot for the record. One good enough to post on limited social media sites (with no detail location information). I stick to this practice when I’m not on our property.
I do not change the in-the-moment behavior of common birds. I only use playback for birds that I hear nearby and they are moving about feeding or patrolling territory. If I don’t hear them I don’t use playback. There is a reason for their silence and it should be respected. If I get them to move a few yards to check out the ‘intruder’, but let them win the sing-off battle, I do not think they are disturbed much less harassed. According to some studies, their status may even go up with the females. All of the birds on this page are ‘common’ permanent or seasonal residents on our property. An interesting thing about the word common as a descriptor is a species may be a ‘common’ sighting by avid birders, but they are anything if not exotic to casual birders, especially the ‘pretty and cute’ ones like Northern Parulas and Hooded Warblers.
I only use my smartphone (Samsung Galaxy) with no auxiliary speakers. I’m acutely aware of how sensitive birds’ hearing is. I’ve missed untold shots because I’ve spooked the bird with the noise of simply being there. There is no need to blast their song. In fact, I think it does more to put them deeper in cover. They’re territorial, not stupid. I stick to this practice when I’m not on our property.
I only play short snippets and at most three sessions. I’m only trying to get the bird I’m hearing close by to move a little closer and hopefully briefly out in the open. When this happens it’s quick or it doesn’t happen or at least I’m not aware that it has. Most often the bird makes a quick pass and lights on a branch not directly in my line of sight. Is this a planned tactic on their part? I’m not sure, but I know that most of the birds I see and take a shot of have come in fast and silently and just out of my peripheral vision. My assessment, at least for these species, the bird is checking the ‘intruder’ and sizing up the situation before full on commitment. If I miss the shot I move on. Incessantly playing the song and keeping the bird from going on with its business is harassment in my opinion. I know I would be irritated as hell. I stick to this practice when I’m not on our property.
I put the camera on low-burst sequential shooting, keep checking my camera exposure settings for changing light and keep presetting focus on the hoped for landing spot . If I’m only going to take one muti-frame shot, I want to make the best of it. I stick to this practice when I’m not on our property.
If I am on a group outing, I openly discuss these points with the leader.