Posts Tagged ‘Territoriality’

A recent research trip took me into the mountains south of Soda Springs, CA.  As I walked along the edges of wet mountain meadows and through stands of huge Incense Cedars, I heard the call of a Red-tailed Hawk.  I looked up to see a single bird souring above me.  As I watched the bird, I heard another Red-tailed Hawk scream.  When I looked higher, I saw two more Red-tailed Hawks circling together much higher than the first.  The pair were both giving their long harsh screams over and over again, and then they both folded their wings and tipped downwards, dropping into the most spectacular, high-speed, tandem, power dive I have ever seen!  The pair plunged down upon the first bird, who was apparently an intruder on the territory of the pair.  The drop must have been at least 1000 ft.  The pair of hawks sped just past intruder, and dipped below taking another pass that the fleeing intruder as they looped back up above it.  The pair then continued to pursue the intruder, diving on it periodically, for as long as I could still see the birds before they dropped into a valley and out of my sight.  A spectacular display and a stunning bit of flying!

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Birds around Davis are in high nesting gear, right now, and along with nest building comes conflicts over territories and mates.  These conflicts can be sneaking stealth raids, small border skirmishes, or fully pitched battles with the combatants hitting hard and fast.  I have witnessed several such battles just in the last few days.  The first was a contest between two male House Sparrows.  They were locked, bill to bill, on the ground rolling over each other as each pummeled the other with its wings.  This wrestling match went on for several minutes and the fact that I approached to within 10 feet or so did not seem to merit any form of acknowledgement.  Finally, one broke away from the others grasp and fled up into the low branches of a nearby tree.  It was immediately pursued by the other who drove the fleeing looser out of the area  entirely.  The winner then flew to a female who had been sitting in tree watching the whole conflict and deciding which male was the worthy mate.

A second vigorous battle I watched was between two male Anna’s Hummingbirds.  This struggle was all aerial!  No fighter pilots in the world have the ability to match what these two birds could do!  Like the House Sparrows, these hummingbirds were locked in a wrestling match, but theirs’ was a wrestling match in three dimensions as they tumbled over and over each other through the air.  Then they would break apart, and one would tail chase the other until they met again and battle was rejoined.  The speed of the whole thing was also quite impressive.  Their combat covered a whole field and in only a matter of 30 seconds or less the conflict was over.  The winner landed in the top of a bush and started bugling his victory at the top of his lungs, and the looser slipped away to try his luck elsewhere.

The last battle of the past week was directly over the quad on the U.C. Davis campus.  It involved four Swainson’s Hawks that were engaged in a bit of a territorial dispute.  Two if the birds, presumably a pair, were very aggressively chasing the other two, also presumably a pair.  The chase twisted and turned through space with the birds diving on each other repeatedly.  One such dive was done with such vigor that it sent the receiver crashing into the top of one of the oak trees that line the quad!  Finally, the resident pair convinced the interlopers to move on.  What really surprised me about this particular battle was that, at least from what I could tell, none of the 50 or 60 people milling about the quad noticed!

So, all in all, a pretty dramatic time here in central California.

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