The Siskin conundrum

This might not work on all browsers, and it might take a while to load, but below is an animated gif to show one of the things I have been trying to work out lately. The Siskins have been here in numbers for a while this winter/spring, more so than for at least 10 years. Siskins, although highly gregarious in the winter months, continually bicker and fight. I don't have a video camera any longer, but my camera shoots at up to around 7 frames a second in good conditions, and the below pictures are shot at that rate.

Effectively this is about 4 seconds worth, and that is quite a long time for a typical display of dominance. The bird on the lowest perch appears only to show submissive posture with the tail closed and the wings held back but is driven off anyway which doesn't seem to be unusual. When attention is turned to the upper bird, their level of dominance seems more balanced with both birds threatening.
The interesting and perhaps not surprising thing I have learnt watching and photographing the spats is that where some pairs seem to have been established and they feed together, the height of the perch on the feeder relative to each other is immaterial, although both will drive off any other bird which arrives to feed. With single males such as the example above, perch height seems very important and indicates dominance. Note the two showing equal aggression above both start on the top perches, it was a slightly unusual confrontation in that the eventual dominant bird in this spat actually chose to take a slightly lower perch.
These longer aggressive displays where birds are leaving the feeder to chase another bird have only been happening of late, presumably as spring hormones start flooding through the arteries and pairs begin to form, but I wonder how much of the pecking order has been determined through the winters squabbles at the feeders.

Which is all very interesting if you are one of the very few people in the world whose brain is entertained as easily as mine.