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Thursday, October 15, 2009

Small Disputes

A holly tree at my place of work has recently become the stage for an ongoing dispute among at least four Anna's Hummingbirds.  The argument was first brought to my attention last Saturday when I investigated the loud vocalizations of two male hummingbirds that were facing off in the branches of the holly.  One bird sat low in the tree, looking up and waving his bill from side to side while chattering away in his distinct hummingbird voice.  The other was about six feet higher, looking down and doing his own vocalizing and bill waving.  While the first two birds were arguing, a third male flew in and buzzed the perch of the bird that was higher in the branches.  The perching bird responded immediately and took off on the the tail of the interloper, chattering like mad all the way.  The bird that was lower in the branches quickly fell silent and slightly retracted his neck as if he now wished to keep a low profile.

On Tuesday I returned to the holly tree to discover a lone male hummingbird sitting high in the branches.  He periodically took short flights to feed on blossoms the tree had produced before returning to hold vigil against intruders from his chosen lookout.  No other birds were seen or heard.  It appeared that either the hummingbird dispute had ended in victory for the bird that was present, or his two rivals were elsewhere at the moment tending to other matters.

Returning to the tree today I discovered a sub-adult female Anna's Hummingbird sitting in nearly the same position as the male that I encountered on Tuesday.  As I watched her, a male flew in and hovered nearby, but she barraged him with seemingly angry chatter that sent him retreating to a high alder branch above.  The birds had two or three more verbal exchanges during the following ten minutes, but neither moved from its perch.  I left them to continue the discussion in my absence, but I couldn't help but wonder what new dynamic will have developed within this group of tiny competitors the next time I visit this disputed tree.   

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