Mobile phones have become an unexpected threat to birds because apps mimicking their song divert them from the business of nesting.
Dorset Wildlife Trust is launching an online campaign to raise awareness after several incidents on Brownsea Island in Poole Harbour.
Visitors to the nature reserve have used apps imitating the unusual "churring" call of the nightjar to attract the birds so they can be photographed more easily.
The trust is advising photographers not to use bird apps on all of its 42 reserves and signs have been put up on Brownsea Island to remind visitors.
The nightjar is rare but enjoys a refuge on Brownsea Island where, like all nesting birds, it is protected under the Wildlife and Countryside Act 1981, which makes it an offence to intentionally disturb any nesting bird.
In addition, Brownsea Island has special protection area status for the habitats it provides for birds.
Chris Thain, reserve manager on Brownsea Island, said: "The apps are becoming quite common, and are great, but their use needs some guidance, I feel.
"I'm sure visitors would be devastated if they realised the possible disturbance they were causing to wildlife. We need to spread the word that use of these apps is not suitable for nature reserves and can be potentially harmful to sensitive species."
Tony Whitehead, from the RSPB, said: "Repeatedly playing a recording of birdsong or calls to encourage a bird to respond in order to see it or photograph it can divert a territorial bird from other important duties, such as feeding its young.
"It is selfish and shows no respect to the bird.
"People should never use playback to attract a species during its breeding season."