It is easy to make. No special skills needed. And very basic tools.
Still the result looks streamlined like proper designer stuff.
Photo's shown throughout this instructable show a big and a smaller birdhouse, both made in similar ways with minor differences.
The blue rimmed one ismy first built and it is the bigger one. Most instructable steps show the second built one.
It depends op the type of bottles you can find, how the end result will look at the end
Step 1: You will need:
strong all purpose scissors
Two plastic detergent bottles
The house one preferably with a more or less square bottom
The roof one almond shaped. See pictures