Expert Comment: Birdsong phone apps 'harmful' to birds?Thursday 13 June 2013
Carl Larsen, Senior Lecturer in Biology at Liverpool Hope, looks at recent research which suggests that birds are being harmed by imitation birdsong from mobile telephones.
In the last decade the availability of smart phones and apps has revolutionised how we live, and this has extended to our hobbies and even research. For decades bird watchers and researchers have used audio recordings of bird songs to attract birds into view. However, the growing and uncontrolled use of such apps has caused the Dorset Wildlife Trust and the Royal Society for the Protection of Birds to request that their use be controlled because of concerns over the potential impacts it can have on breeding birds.
Nesting birds are protected under The Wildlife and Countryside Act 1981, which states it is an offence to intentionally disturb them and playback can be interpreted as disturbance. Such laws are even more stringently applied to endangered or threatened species.
Such bird song apps work most effectively on territorial species during their nesting season, which mistake the recording for a rival threatening to encroach on their territory or cuckold their mate. The territorial male will typically confront the intruder by patrolling the edge of its territory and singing, or it may stay silent and mate guard against an adulterer. For her part, sometimes the female will approach the recording to assess the new male and may even solicit some attention.
Some of the potential benefits of playback include a reduction in disturbance – i.e. a reduced need to physically enter the bird’s habitat and because it is species specific it reduces disturbance to other species. Research also shows that infrequent use increases the social standing of target males by increasing their territory holding power.
Some of the potential consequences include the desertion of territory by the loosing male, leading the female to seek extra-pair copulations. This is a particular risk if the female is not incubating or brooding chicks. Playback causes unnatural stress wherein the territorial male wastes energy chasing a phantom intruder exposing him to predators and distracting him from other activities, such as foraging.
Effects that have been documented include raised testosterone levels in males, and increased maternal behaviour in females exposed to playback. Researchers generally agree that the effects of playback are poorly-known, but are probably (paradoxically) both far-reaching and insignificant.
Birds also use song/playback to show off and confuse one another. Marsh warblers mimic the songs of other birds to show how intelligent they are to females and individual great tits vary their song from different parts of their territory so that neighbouring males think there is more than one male singing.
I have used playback to capture territorial male nightjars featured in the article. We followed very strict guidelines, which included, a single 30 minute bout of playback once each week (or until the male was captured), use only after male has established his territory and where the nest site was known, and a restriction on the volume of the song. Under no circumstances should you play a recording continuously or at very high volume. The epitome of bad playback etiquette is the person who walks around with a device continuously and loudly broadcasting sound. This is ineffective, unnecessary, and is the kind of playback most likely to be harmful to birds and disturbing to other birders.