The Issues Committee for the Wisconsin Bird Conservation Initiative has recently published Ethical Standards in Birding (Protecting Endangered, Threatened, and Rare Species). This is a great code to follow for birders and bird photographers alike.
I do not play tapes to lure birds in for pictures and I know that the portraiture I capture will always be a step or two below in composition and quality by comparison...and that's just fine. I much prefer staying in the same spot and waiting for something to happen rather than plowing through habitat or forcing the situation with a bird by using recorded bird songs. And remember just because you think nobody can see you...the birds are still watching you!
Fox Sparrow image © Michael Allen McDowell