Just fended off my first big siege (with elk bird mounts!). Despite being in the process of reorganizing the new catapault battery, I had no injuries to the surviving dwarves, although only a single death: a master lasher caused a speardwarf recruit to pass out on a serrated disc trap. He was minced for several minutes before his steel armor was pierced. My 3-dwarf hammerlord squad imploded the heads of nearly fifty goblins, and the axe/spear squad got another forty or so. The speardwarves' adamantine spears had been covered completely in forgotten beast blood in earlier combat, of course, so goblins were rotting left and right when they joined the brawl. The hammer lord/militia captain's companion axe lord did well too, I just found a goblin head ~150 Urists away, all the way down the main staircase on the magma level as a result of her performance.
For some reason, an axegoblin got her right arm chopped off, then managed to run past the entirety of the two squads, down the main stairs, and into the cavern, where she was mauled by a giant cave swallow and stumbled onto a cage trap. I got the swallow too. Perhaps I should let the two finish what they started. The axegoblin is my only prisoner, so I might just use her to test my single-wooden-spike room... heh heh.