They're Khaki Campbells. I thought they'd be too big for a hawk, but maybe one tried anyway and failed.
I haven't seen anything recently, except for vultures but we see those all the time and they've never been a problem.
I had two drakes and that's it. No females. I hoped they'd get along well since they grew up together, but one started getting aggressive with the other recently and they just turned one year old. Well, the aggressive one has been trying to mount and mate the other, both in and out of the water...