This is the finished product.

Used 1 x 4 x 6 ft dog eared fence boards which we had already (can use pallets). We cut them in half making it about 3 ft high and painted then as to the colors we already had. They soon become different heights. We had lots of extra fence pieces around which we used to make the roof tops. If you noticed they were stained and placed at different shapes and sizes.

Now that they have the roof tops on and different heights, also drilled the little holes and placed the little perch posts on. Now its time to just connect them together at width you want. We used two 3 ft boards one at the bottom and one just below the holes. Bingo! Basically its done.

Different roofs.

Close up of the tops.

Final picture includes birdhouse's & bench.