[Tweeters] Anna's bullies out rufous?
creinsch at humbirds.org
creinsch at humbirds.org
Mon Apr 9 10:01:49 PDT 2012
Although we are only a short distance from Discovery Park, which is sometimes rife with Rufous, in Spring our yard is visited rarely by them. (I suspect they are busy "hooking up".) But last year in early summer, for several weeks, there were a number of immature Rufous in the flowers here, and they could out fly and out dodge the Anna's with ease. We have had Summer and Winter resident Anna's for the last 10 years and this has not prevented South bound Rufous from stopping for a refill in August and early September.
Here is an excerpt from a post by David Hutchinson back in Feb 2009 about this very subject:
"..... have had an interesting note from Hal Opperman. In the same Natl Audubon Society article quoted in the P.I and on MSN, it was suggested that Anna's "aggression" is reducing the numbers of Rufous Hummingbirds present in their regular habitat. (Have NOT read full NAS paper). Certainly to my knowledge there is not a scrap of evidence that Rufous Hummingbirds are declining in their general numbers, certainly not from aggression from Anna's hummingbirds.The provisional results from the Magnolia feeder survey and Discovery Park study which I ran in the early 1980s suggested that inter-specific aggression between Anna's and Rufous varied by time of year and for different reasons at feeders, with dominance going back and forth.There was no observable aggression that suggested "aggression" as a limiting factor in the wild areas where they occur congruent to each other.What I have read in the literature suggests the same picture between Anna's and Allen's in the south of their range. Hummingbirds are simply opportunists, but there is certainly much to know."
Perhaps David has an update? I would be interested in hearing others' observations as well, but, a few years back, a writer from BC went on at great length about "the threat of Anna's", and I hope this does not turn into a repeat of the recent banding "discussion".
magnolia, seattle, wa
----- Original Message -----
From: Joe Dlugo
To: tweeters at u.washington.edu
Sent: Monday, April 09, 2012 8:36 AM
Subject: [Tweeters] Anna's bullies out rufous?
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?
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