Yup. They're the feathers from a turkey's rump. The reason they look different on a mature bird is the marabou you usually see for sale to make fishing flies are immature feathers from young birds.
The original marabou feathers originally came from the marabou stork, but since the stork is CITES listed these days you're probably never going to see the original feathers for sale. You might see one in a zoo, but if you do you'll probably wish you hadn't. It's one of the butt-ugliest birds alive.
Some interesting info on marabou here:
http://www.lab.fws.gov/idnotes/MarabouIDGuide.pdf
Don't worry, catch crappie.