I've had quite a bit of luck with keeping the sparrows
at bay by using only black sunflower seeds.

I've read in places that one way to discourage the
sparrows is to place your seed in a feeder that swings.
It seems sparrows prefer to eat from a stationary feeder
and dislike the swinging feeders.

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Thanks:

James Knapp
Seattle, WA
jcknapp at juno.com