Ah, nothing stirs up debate quite like ice-storm induced cabin fever...

First, let me say that I only feed birds (other than hummingbirds)
during a
fairly narrow deep winter window and that it's almost entirely because I
can't get out birding as much as I'd like. The neighborhood cats are
the
primary reason why I don't feed over longer periods. I am approximately
ambivalent about birders as bird feeders, like starlings, are ubiquitous
and I choose my battles carefully.

But since somebody mentioned science, I figured I'd point folks to some.

1) Correlative does not mean causative.
Anna's Hummingbirds are not the reason why Rufous Hummingbirds are in
decline. Rufous Hummingbird declines predate significant arrival of
Anna's Hummingbirds by at least a decade as a quick check of the Breeding
Bird Survey database would show ( http://www.mp2-pwrc.usgs.gov/bbs/ ).
The more probable culprit: habitat degradation, particularly forest
fragmentation and loss of large tree forests with healthy understory.

House Finch/Purple Finch correlations probably don't equate to probable
cause either. I'd bet this is also probably a habitat loss issue.

2) Forest fragmentation or feeding?
Study after study has shown that fragmentation of habitat is the single
greatest cause of nest predation. A lot of fragmentation is associated
with residential development and development may concentrate some predators,
particularly cats, raccoons and opossums, but given all the garbage and
pet
food resources, bird feeding is at best contributory not causative.
BRITTINGHAM, M. C., and S. TEMPLE. 1983. Have cowbirds caused forest
songbirds to decline? Bioscience 33:31-35.

BRITTINGHAM, M. C., and S. TEMPLE. 1996. Vegetation around parasitized and
non-parasitized nests within deciduous forest. J Field Ornith. 67:406-413.

TERBORGH, J. 1989. Where Have All the Birds Gone? Princeton University Press,
Princeton, NJ.

Cats Indoors online at: http://www.abcbirds.org/cats/

3) They'd die without us....
The main difference between feeding and not feeding is that when you feed,
birds are easier to see from the kitchen window. Again, this is pretty
well studied and no significant difference in survivorship has been found
feeder vs. no feeder. In fact, feeding has been shown to reduce reproductive
success in gulls (and possibly ducks) who get fed bread and Freedom
fries because they are so low in nutrition.
So, the better statement would be: They'd move somewhere else if I stopped
feeding them.
Brittingham, M.C., and S.A. Temple. 1992. Does Winter Bird Feeding
Promote
Dependency? J. Field Ornith., 63:190-194.

Wells,J.V., K.V.Rosenburg, E.H.Dunn, D.L.Tessaglia-Hymes, and
A.A.Dhondt.
1998. Feeder Counts as Indicators of Spatial and Temporal Variation in
Winter
Abundance of Resident Birds. J. Field Ornith., 69:577-586.

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

Half-a-bee, philosophically must ipso-facto half not-be.
But half the bee, has got to bee Vis-a-vis its entity...
d'you see?
But can a bee be said to be or not to be an entire bee
When half the bee is not a bee due to some ancient injury?
-Monty Python

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