Re: Forward: "Rufous Peace in Panguitch"

[Mark Stackhouse <westwings at sisna dot com>]

The phenomena is called resource swamping. When there is an ample resource (your hummingbird
feeder) and a large population of birds wanting that resource, there simply isn't time, nor a
benefit, for one bird to try to monopolize that resource. In such a situation, the bird which
tries to keep other hummingbirds from your feeder spends all its time driving other hummers
away, and doesn't get any time to feed. Because the resource is ample, there isn't any benefit
to being territorial anyway, as the bird can feed as much as it needs to without depleting the
resource - more or less regardless of how many other birds are there.

The thing which drives this phenomena is the population of birds using the feeder. In valley
locations, such as at my house, I rarely have enough hummingbirds around for this to occur.
People with feeders in the mountains, on the other hand, see this often. I remember one morning
in the spring a few years back when I was able to watch the threshold being crossed at my
feeders. It was a stormy day, and many more hummingbirds than usual showed up at my feeder. At
first, there was the usual combat, with birds chasing one another very aggressively. Then, as
more and more birds came in, the chases became shorter, and other birds slipped into the feeder
while the aggressors were busy, until the feeder was surrounded by a hovering cloud of
hummingbirds that became more and more tolerant of one another. They drew ever closer to the
feeder, until all of the perches were filled double with other birds patiently waiting their
turn. It was an amazing transformation in behavior to witness in the space of a few minutes.

Good birding!

Mark

Mark Stackhouse
Westwings, Inc.
1432 Downington Ave.
Salt Lake City, UT 84105
(801) 487-9453
westwings@sisna.com


Utah Birds wrote:
> 
> From: Cathy Woodard
> Date: Tuesday, July 30, 2002 at 23:11:44
> Subject: Rufous Hummingbirds
> Email_Address: pvl@scinternet.net
> 
> In reference to the recent posting about Rufous Hummingbirds not sharing: We have had them at
> our feeders for at least 8 - 10 years and as stated in the posting, they have never been
> willing to share. However, this year is different. We have a dozen or more Rufous, even more
> Black-Chinned and Broad-Tails coming to our three feeders. The first week or so, the Rufous
> were standing guard over all three feeders and attacking all who came near. This past week,
> all of a sudden, they have become sharers even going so far as to share the same perch with
> others without regard to species or sex and lining up on the deck rail to await their turn. We
> have been watching in utter amazement and can't explain the phenomenon, but we're enjoying it.
> 
> Cathy Woodard
> Panguitch
> 
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