If  he is doing "j" dives,  that is also a territorial display as well.   It can be done to male Anna's as well as other bird species as well. 
This is also the time of the autumnal recrudescence, when the ratio of daylight:darkness is the same as in the spring.  This tricks the birds into thinking it is spring and drives them to mating behavior for a period of time. 

Bill Anderson; Edmonds, WA. USA
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