Rob,
You asked:
Do they compete with, perhaps drive out the native Rufous
hummingbirds?
I live near Wallace Swamp Creek Park in Kenmore and monitor the birds
there almost every day.
Several Anna's (at least) 4 winter in the park. (maybe they go to
neighboring houses to find nectar feeders) each has a territory staked
out and I can almost always see them on their respective perches each
time I visit the park. Last spring when the salmon berries began to bloom
the Rufous returned and the first thing I noticed was that a Rufous had
taken over the favorite perch that one of thew Anna's had been using all
winter. From that observation I would say, if they do compete with
Rufous, it's the Anna's that come out on the loosing end of the
competition.
This is my own interpretation, based on one observation. Any Hummer
experts in Tweeterland? Fee free to set me straight.
Linda Phillips
Kenmore 98028-2616
sweetmem at juno.com