Extracting a crest from a cockatiel is very difficult. I just get as much as I can and lose the rest, and sometimes I draw some crest feathers in.
If you have the professional version of Photoshop (not the much-cheaper Photoshop Elements software that most people use), there's a complicated technique that will let you do it. I think that maybe the very newest version of Elements will do it too, but I have Elements 8 which is too old to have some of the commands. There are a lot of online articles about how to do it. Search for photoshop extract hair, because selecting flyaway hair is a much more common problem than selecting crest feathers. Here's one article as an example:
http://www.photoshopessentials.com/phot ... ting-hair/ It makes my head spin just reading about it.
Bluekeet, what's the artistic element in your picture? Did you black out the background? Because the bird chewing on the bow looks very realistic, and if you extracted the bird from a different picture I'm jealous of your skill lol.