Leighton, nice recording there - and experience says to me that was not a kill scene. Once they get something hurt or down they are all business and normally silent. I'm no expert on why they call and how, but have heard them unceasingly for over 20 years. The normal times for that sort of sounding are at or near dusk when they are gathering somewhere (probably dens) or communicating at some distance with others. Females in heat will make a distinct type of barking sound when alone
At 3am out of the blue - unless some other something was unexpectedly into their "territory" and they were dealing with that, I have no guess regarding the prompt.
