My iPod holds a few Willie Nelson songs, some Mozart, and the songs and calls of hundreds of North American bird species. The bird songs are what I consider most important. I use them to refresh my memory of who sings what. I use them to check on a heard song or call, to put a name to that. And I have used them to pull birds into sight. The iPod, with an attached set of small, inexpensive Radio Shack speakers, is perfect for the job. You can even set the iPod to loop that particular sound cut, to play it over and over and over.

The use of recordings is not uncommon among active birders. It works best in the spring, when birds are singing and territorial boundaries established. You hear the bird. You can't see it because it's in the middle of a thicket or way up there in the tree canopy. If you play its song, however, there's a chance that it will perceive your iPod as a rival, and fly in to investigate. That can give you the look you want.

This is a debated practice. Once upon a time a birder had to carry a bulky tape machine and a pocket full of tapes. Finding the song you wanted could involve a lot button work – running the tape forward and backward to get on target. It was clumsy and time-consuming work. Some serious birders did this, including guides who had a financial commitment to find certain birds for clients.

It was understood that you could over-tape a bird. You could get to the point where the bird ignored the repeated call. Or, could so stress this territorial creature that it would leave to try again elsewhere. These possibilities were known and accepted in what then was a rather small and tight birding community. Abuse was at a minimum.

Two things have changed this scene. First, there are more of us, more birders in the field, which is wonderful. Broadening participation, however, has not always been accompanied by broadening knowledge of do's and don't's. Second is the convenient iPod or its cousins, and the ease with which you can find recorded bird songs and load them into the machine. The growing popularity of bird photography is another factor. You can't photograph the bird if you can't see it.

All of this has increased the volume on a log-running argument about the ethics of taping. Does it stress the bird? Does playing a song only once stress the bird, or does it take significant repetition? Is this stress meaningful? Does it harm the bird? There are advocates who answer those questions both yes and no.

A recent article in "The Seattle Times" addressed these questions. The article, by reporter Sandy Doughton, included comments by the director emeritus of the Slater Museum of Natural History in Tacoma. He is a birder. He has an iPod and a set of pocket-sized speakers. For the purposes of the interview he went into his backyard and called to the fore a chickadee. The bird responded with its own call once. Getting no response from this phantom rival, it went back to its own business.

Dr. Slater said to the departing bird, "I promise that I'll never do this to you again." He says he believes the use of recordings does stress the birds, but calls it "a very, very short-term stress." He uses recordings rarely, and only when he believes that the bird will never again encounter recorded song.

Other Seattle birders took different positions. The president of the Washington Ornithological Society said he will use a "snippet" of song from a recording, but strongly disfavors over use. The director of the University of Washington's Center for Conservation Biology said response to recordings can include anxiety, exposure to predators, and an unguarded nest and mate. A wildlife-recording expert quoted in the article said she is "dead set against" use of recordings. She says you can hear the stress in the voice of a responding bird.

A biologist found that birds confronted with recorded song had testosterone levels 10 times normal, levels that maintained themselves for as long as two days. His field research has caused him to quit using recordings during recreational birding.

Birders will find parks or refuges where use of recordings is regulated. In national wildlife refuges, for example, the use of recordings to attracting birds is not forbidden, but birders are expected to use discretion and good judgement if doing so. Any time refuge enforcement personnel believe someone is using recordings to the point of harassment, they have the authority to stop them.

Obviously, opinions differ. If there's a bottom line for this it might be judicious use if use at all. For certain, don't step out of your car with iPod in hand, song at the ready, consequences ignored. Understand what you're doing if you're going to do it. And think twice about the bird. The bird is more important than seeing it.