My general feeling about using tape to see birds is simple:

What's the hurry? You don't get to see 'em one day, then
you have an excuse to come back the next. I deeply wish
that we birders could wean ourselves of the have-to-see
mindset, but that's just one birder's opinion in a rich and
varied world of birder opinions....

It took me 20 years to SEE a Northern Saw-whet Owl and I
have to say that sometimes the trials and tribulations about
not being able to see a bird make a better story than seeing
a bird (Sayre saw it fly while I was pointing the flashlight
the wrong way; we had that little tree surrounded and still
couldn't find the bloody thing).

The ABA allows for the inclusion of heard-only birds on
one's life list so we no longer HAVE to see them. So, I view
playback as an option to be used judiciously.

For the most part, tape playback is an issue in areas where
it's a daily (or hourly) nuisance, so I have used the technique
to elicit responses from owls and rails for Christmas Counts,
but only long enough to get the response then I quit. I would
strongly recommend against the use of playback during breeding
season for the target species or at parks and refuges.

--
Mike Patterson
Astoria, OR
celata at pacifier.com

http://www.pacifier.com/~mpatters/bird/bird.html