dougiewainwrights bestämningar

Noticed a bird harassing a tern near a large flock of shearwaters offshore; I was struck by the agility of the pursuing bird (reminded me of the frigate birds in the Galapagos). A second bird joined in; I snapped a couple of photos from the shore and after cropping them heavily came up with these, which look to me like pomarine skuas, with one bird being a dark morph. I'd appreciate confirmation or correction of the i.d. if that's possible from these photos (sorry about the quality, but these were the best I could get under the circumstances).

Anyone else seen these recently around the harbour?

(Updated in light of epitree's suggestion that they might more likely be Arctic skuas.)