Subject: [Tweeters] hummingbird feeders and migration
Date: Oct 14 13:15:55 2005
From: Dennis Paulson - dennispaulson at comcast.net


Hello again, tweeters.

Anna's Hummingbird is essentially nonmigratory, so if it breeds north
to BC, it winters north to BC. Birds are great dispersers, and there
are plenty of records of the species away from the breeding grounds,
but that happens with most bird species. Anna's has surely spread far
and wide from its original range in California and SW Oregon because of
hummingbird feeders that support it. I think these have been more
important than flowers. We have a lot of hummingbird flowers in our
yard of many species, but none of them extends through the winter, and
I suspect we wouldn't have resident hummers if we didn't have feeders.
They also feed on small insects, as has been said, but these also get
very scarce on the colder days of winter. I think only one thing
supports them at certain times - the feeders.

At the same time, my guess is that if you stopped feeding your hummers
in winter, they would not have to go far to find other available
feeders. You might be surprised at how large an area a hummingbird
covers in its daily foraging. I often see one leave my yard and fly up
over the nearby trees, heading off into the distance somewhere.

As well as affecting a resident species such as this, I think
hummingbird feeders have had a profound effect on hummingbird migration
patterns. Years ago when I was in NW Mexico in September, I couldn't
believe the number of hummers at the many kinds of hummingbird flowers
there. All of our migratory western hummers were there. I was just down
in the same areas last month, and I was shocked at the virtual absence
of hummers at the same flowers. I speculated that the reason was that
they were all stopping in Arizona at the thousands (millions?) of
hummingbird feeders available for them there. Everywhere we went in SE
Arizona, there were clouds of migrant hummers at feeders. It's become
one of the spectacles of the "natural" world. My suspicion is that
these are the birds that were missing from the Mexican flowers, and I
wondered if we were inadvertently causing the decline of many plant
species that depended on hummers for pollination! I hope there are
biologists looking at this. It should be easy to answer the question
"are migratory hummingbirds staying much later in the Southwest than
they used to?"

Dennis
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Dennis Paulson
1724 NE 98 St.
Seattle, WA 98115
206-528-1382