I'm no expert on this but I have a theory. While the Rufous Hummingbirds are "vacationing" in the tropics over the winter, the Anna's Hummers are still up here claiming territories. So when the Rufous Hummers come back, they end up "trespassing" on territories already claimed by the Anna's.

Barry Ulman
Bellingham, WA.


On Apr 9, 2012, at 8:36 AM, Joe Dlugo wrote:

> Just three years ago rufous hummingbirds were plentiful in spring in my neighborhood. Every 150' or so, they'd occupy the prominent treetop. Three years ago was also when we started seeing Anna's H-birds in winter, and subsequently in spring. The Anna's population is so great now that this bird that was non-existent a few short years ago is now the most common neighborhood bird besides chickadess. Now I notice just one rufous h-bird keeping a territory. Just wondering if anyone else has had a similar experience. I was under the impression that Anna's would lose out in any territory squabble to the uber-aggressive rufous. Maybe that is still true but perhaps there are other factors in play?
>
> -Joe Dlugo
> Lacey, WA.
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