Section concerning Woodpecker
A woodpecker is an animal. The description of the woodpecker is "A black bird with a red cap.". The woodpecker is undescribed. Understand "bird" as the woodpecker.
A birdhouse is a home. The description of the birdhouse is "Looks comfortable. [if occupied] It's occupied by a woodpecker.".
Instead of transforming the healthy boards:
if the player is carrying the tools:
say "You construct a nice birdhouse out of the planks.";
now the healthy boards are nowhere;
now the birdhouse is carried by the player;
the birdhouse hints in three turns from now;
otherwise:
say "You could build something out of the boards, but you lack the tools.".
After inserting the birdhouse into the tree:
now the birdhouse is suitable;
say "You secure the birdhouse to the tree.".
Instead of taking the birdhouse when the birdhouse is in the tree:
say "The birdhouse looks fine where it is.".
Every turn when the birdhouse is suitable for the third turn and the birdhouse is empty:
say "A black bird with a red cap flies to the birdhouse, inspects it, and starts to make itself at home .";
now the woodpecker is in the location;
acquire woodpecker;
now the birdhouse is occupied.
At the time when the birdhouse hints:
If the birdhouse is unsuitable:
If the birdhouse is carried by the player:
the birdhouse hints in three turns from now;
otherwise:
say "A bird lands on the birdhouse, peers at it, jumps disdainfully and flies away.".