Hej,
Wow you got birds I will never see here... Except the woodpecker and the goldfinch, but I got the european one, which is very beautiful anyway.
Most of these pics are very good, though you seem to lack some light there (most are at 1/60), flash. At least you should use ISO 100 (not much difference with ISO 80 for noise) and a bigger aperture, though maybe F4 is the best you can get a these focal lenghs. Not sure the birds like the flash, anyway. Can't you do this in day time and when there is plenty of light available ? Or is it always too dark there, anyway ?
I put my cam only on bright sunlight to make sure most of the pics with a bird on are sharp movement-wise (the focus can also be wrong on some occasion, but I now handle that kinda well) and never used the flash because I fear it's not good for the birds, and they may not come back soon after being flashed anyway, or do they ?
And don't worry too much about pictures without birds, I got 1000's of them too, 1 very good picture out of 100 is a good enough rate for me.