I think it important to tell yourself that you are not trying to re-create the exact likeness of a bird, but making a wooden carving based on the subject that, while celebrating the qualities of the wood, tells people something about the form of this beautiful creature.
As you can see from the photographs, this bird had seen much handling and was getting a bit bedraggled.
Right: This piece was first developed by roughing the main form with flat and half-round floats (ie not rasps) and files. I found them as convenient as sculpting with gouges.
Illustrated: A flat float, a half-round float (Sandvick) and a round Surform tool can rapidly move material.
Left: Cheap files bought as a set in a plastic pouch from a DIY store, heated to red heat and bent by pressing with the end reating against a hard surface. These will serve quite well if kept for use only on wood.
Frequently use filecard to clear the teeth.
Some might think that messing about with files and what not is hardly "proper carving". Proper carving is done with round mallets and sharp gouges, isn't it? As far as my owl is concerned, some deep hollow areas have to be excavated and such features as the wings and tail feathers have to be modelled. The time for "proper" carving has arrived.
I don't think that a blow-by-blow account of gouge cuts will be all that helpful, but some general principles might be helpful. Please hop to Gouge Obedience Training