Stanley Tate  We value what is rare  We value what is rare. We
can't help it: twentydollar bills are rarer than pennies,
beautiful girls are rarer than plain ones. And it is one of the
facts of life that there are more common birds than rare ones.
There is a popular notion that all birding is about rare birds.
The reason for looking closely at a flock of sparrows is to see
if there is some bird of indescribable rarity lurking among its
common companions. If it isn't there, you ignore the sparrows
and look elsewhere.  What is a rare bird? You could say that a
rare bird is any bird that nobody sees very often. Or it could
be any bird you haven't seen yourself. The Scarlet Tanager is a
bird that eluded me for several years; but now I live in a place
that Scarlet Tanagers like and I see them frequently, so Scarlet
Tanagers have gone from rare birds to not exactly common birds,
but certainly birds that are part of the routine of my life.
What about the Magnificent Hummingbird? You won't find it in
your Sibley's