Thanks, everyone. I hope my next attempt goes through okay and I finally get it. This is the last achievement I need, so it's extra frustrating. XD
I do okay on food in the later parts of the game. I get to the archipelago and spend generations just gathering, trying to get about 1000-1600 food and 100-200 nesting material. Through the rest of the game, I'll gather when I can, but this way I have a good buffer for the harder islands and can just skirt the shoreline to rush to somewhere a bit more plentiful when I need to...or, like in the winter island where you're stuck (right before Home), just hunker down in a group around a nest or two and wait things out.
As for my preferred build, I go for nimble fingers as soon as I can, and cracker jaws and some kind of horn. Fishing tails are nice too but lowish priority. Once I've got my food store where I want it, I try to trade the nimble fingers for wings to help me breeze through the islands faster (and I have a system on islands with trees that works very well for me but depends heavily on that cracker jaw). I love the look of the bearyena stuff but they move so slowly.
