For a seasonal supplement to your regular bird feeder, cut a 3- to 5-pound pumpkin in half; scoop out, leaving a 1/2-inch thick wall. Cut a 1/2-inch-deep groove in the rim for pumpkin seeds. For perches, poke holes and insert twigs. To hang, knot two lengths of twine together in center; tack knot to feeder bottom. Fill with birdseed.
Pumpkin Bird Feeder
A seasonal supplement to your regular bird feeder.
Martha Stewart Kids, 2002

What about using a foam craft pumpkin instead then it could be used for a longer period of time and possibly next year
I wonder if allowing the pumpkin to dry a bit and then smearing the inside with peanut butter or melted suet would allow it to hold up a bit longer and stop the mold...?
I think it is really cute but not good for the birds. They are delicate and the pumpkin will allow the seed to grow bacteria really well. If you do it then one day supply of seed and toss the pumpkin.
By cleaning it out to 1/2-inch walls, there isn't much left to rot. You might want to let it sit, clean, for a day to dry, before putting seed in it
I think by cleaning it out
That is my concern too, how do you keep the pumpkin from spoiling too fast? I really like the craft idea and would like to do it, we do not celebrate halloween so I would be cutting into a fresh pumpkin.
My pumpkins rot when they are cut. It only takes a few days to turn them into sticky, drippy, moldy soup.