Willow bird houses are used in setting bird house traps on Fossil Island, requiring a Hunter level of 24 to use. They are made by using willow logs on a piece of clockwork while having a hammer and chisel, requiring a Crafting level of 25, and granting the player 25 experience.
The bird house must be filled with hop seeds as bait, up to a maximum of 10, or 5 if using wildblood seeds. After doing so, the bird house will passively capture birds. It can trap up to ten birds, granting 560 experience if the birdhouse is full, which will take approximately 50 minutes.