Depending on the approach you take, it doesn't look too tough. With expanding foam, if you carve away too much you can always add more. As a novice, I would probably carve a simplified shape, and use paint to do the detailing instead of trying to carve out the details such as the face and maybe even the "feathers" on the wings. Make the wings flat; paint on the feathers.
You'll definitely want to make a core out of something like cardboard and wire, or Sintra sheets, or MDF, and make sure the interior has a sturdy "skeleton" - otherwise you'll risk having the wings snap off.
Also, I like to use a metal rod to reinforce the pointy bits such as the wingtips and the triangles at the base. Those will be very fragile, prone to crushing or snapping off. So get a length of metal, such as a clothes hanger, or for something thicker I used the metal stand from one of those cheap little roadside signs (I scavenged a handful of them around election time). Build your sculpt around it; or, once most of the sculpt is done, drive the rod into place with a hammer. I did this for the pointy bits on Marceline's Axe Bass that I built for my wife, and it was very sturdy; you could rest the pointed axe tips on the floor with no structural damage at all, though I did have to touch up the paint after the con.
You might also think about making the staff head and foot detachable, for ease of transport and storage.