Level 3 Elite Harpy: Initiative +2, HP 90, AC 17, Fort 14, Ref 14, Will 16, Claw +8 1d8+1
So it would have had more hit points, but been much easier to damage. I think that's the way to go. So note to myself: if I don't want to have ten monsters in every encounter, scale 'em down and make 'em elites.
EDIT: Followup — I have retooled all of the encounters I had already prepped so that no single critter is higher than 4th level (although several of them are elites). However, by the time the characters get through what I have prepared, they will probably be knocking on the door of 2nd level ... so for the parts I hadn't finished yet, I'll have to start using 2nd level assumptions. This also means I need to go back and add a little more treasure, I expect, but that's okay. There are a handful of "caches" about the island that can have a bauble or two added easily enough.