Is it cruel/unethical to playback bird sounds to birds in my yard?

Question

I am an underwater acoustician…so am very not up to speed with the bird acoustics world. However, I started enjoying bird watching in my back yard at the start of the pandemic. I use the Merlin app to identify birds I see. Within the app there are several example sound files of the different call types that species produces.

In one instance I was sitting my my deck and identified a Carolina wren (fun little guy!) I was exploring the sounds they make to try to learn to identify them by sound but then when I played it from my phone it flew over and was looking around and flew very close to me and the phone. I assume it was upset about another ‘bird’ in its territory.

My question is…in the bird acoustics world is this viewed as cruel or is it frowned upon? Or is the occasional at home ‘playback’ acceptable? In the future I could go inside to listen to the sounds.

Answer 1

Bird biologist here. The short answer is to think of playback as you would any other disturbance: it may not seem like a big deal if you're the only person doing it and you're only doing it briefly, but if everyone does it, it becomes a substantial problem.

It might help to think about the function of the vocalizations: if you play song, the birds are most likely responding to a territorial threat; if you play many types of calls, the birds are responding to a distressed conspecific and/or potential predator. All of these are stressors, and all of them are going to remove birds from what they should be doing at that time (feeding young, defending territories from real intruders, avoiding real predators). The more you do this (or the more people doing it), the more harm done. Birds change their foraging and parental behavior depending on their perceived risk of predation; when caring for young, even short periods off the nest or not feeding can reduce survivorship or condition of the young.

Researchers will use playback to investigate the functions of vocalizations, of course, and also to catch birds. Increasingly, however, we try to limit the duration of playbacks as much as possible. (I'm not sure that extended playback of vocalizations would pass current ethical review in the US, although rules for this sort of thing vary considerably.) The Audubon Society recommends avoiding use of playback (see: https://www.audubon.org/news/why-photographers-should-reconsider-using-playback-field)

Answer 2

I'm not a bird acoustician specifically (I do primates), but in general we try to avoid playbacks as much as necessary just so we're not messing up their behavior or stressing them out. But I think it really depends on the context and frequency with which you do this (once every few days I wouldn't think is as big a deal).

When we do playbacks for sound transmission experiments with lemurs, we actually used a non-lemur call that was similar in acoustic structure to try and limit the disturbance. Of course, it was still a novel sound which could be stressful in and of itself but we figured it would be better than an actual real lemur call itself.

So basically, I don't think there's any "standards" for this, and in my opinion it's best to limit disturbances to the best of your ability and as reasonably as you can given study aims, etc.

There have been some studies looking at such effects (but not many) e.g., -

An experience to remember: lifelong effects of playback-based trapping on behaviour of a migratory passerine bird.

Call playback artificially generates a temporary cultural style of high affiliation in marmosets.

What is the effectiveness of using conspecific or heterospecific acoustic playbacks for the attraction of animals for wildlife management? A systematic review protocol.

Some guidelines we use widely in primatology -

Bioacoustic Field Research: A Primer to Acoustic Analyses and Playback Experiments With Primates.

Answer 3

In my opinion, outside of a scientific context, lures of any kind should not be used - so no tapes either. There are studies that show that birds (e.g. woodpeckers) sing more intensively for several days after being provoked with a tape. That means they lose a lot of energy. This energy is then lacking at the latest during the rearing of the offspring. It can often be observed that birds even give up their territory when vocalisations of a supposed rival are played during the time of territory occupation. Especially since we usually know very little about the respective exact function of the vocalisations on tapes and may play extremely aggressive songs without knowing it. All of this speaks for me in favour of not using them outside of a specific question.

In Germany, the use of tape lures is even strictly forbidden, with heavy fines. A permit is required for scientific work. Unfortunately, it has to be said that hardly anyone adheres to this and that the use of tapes in nature photography is very widespread.

Answer 4

Hmm, underwater acoustician here too, and I don't know the answer to this in a hobbyist context, but I do know that the bird ringing community in the UK do this in a different context.

Background: The bird ringers put tiny lightweight rings on bird legs of birds that get entrapped in mist nets, and then whenever that bird is recaptured in a mist net (by bird folks all around the world), the numbers on their rings are recorded, and this helps to build up a picture of their movement patterns, longevity, plumage through age, etc. Been done for decades.

I have been with established and qualified bird ringers in England while they put a little speaker playing songs of a bird of interest right next to the mist net, with the goal of attracting real birds of that species to run into the mist net. So this is a kind of wild playback where no permit was needed, and where it wasn't looked down upon.

I imagine it would be looked down upon if they left it there longer than the half day or so that the mist net was up, and look forward to hearing from the ornithology community on further/general ethical stances.