There are so many interesting components to a bird that I can devote an entire post to just the head and neck.
The brain is very different than mammalian brains. There are homologus structures but overall appearance is very different.
Birds have reletively large optic lobes and relatively small olfactory lobes which may reflect the relative importance of vision and relatively poor sense of smell in some birds. http://people.eku.edu/ritchisong/birdbrain.html
Birds eyes have incredible variability in size, location and specific function depending on the type of bird. For example. Owls are predators and need good depth perception so they have eyes in the front of their head like humans. This allows for stereoscopic vision and better depth perception. Birds that could be considered prey species such as parrots and passerines have eyes on the sides of their head. This improves peripheral vision so they can watch for predators. For great article on avian eye anatomy and how this affects vision for different species, please see: http://www.birdsnways.com/wisdom/ww31eii.htm
Lets move on to bird beaks/bills. The beak is a more complex structure than people realize. The beak has the outer keratin layer that is the aspect that we see.This layer is similar to our finger nails. Under this is a layer of connective tissue, blood vessels and nerves and then bone. There is the upper beak with an underlying maxillary bone and a lower beak with an underlying mandibular bone. As a vet, I have seen my share of beak avulsions. This means that due to some trauma, the upper beak or or lower beak (or both) have been torn off. It is sometimes hard for people to understand why this doesnt grow back since they know they have seen the beak tip grow when broken. The reason is that the tip of the beak is the end of the karatin layer and the keratin layer is regenerative. As long as the base of the keratin layer near the cere (fleshy aspect near the nostrils) has not been damaged, the outer surface of beak will grow out (just like your fingernails). However, once there is bone involvement, there is permanent damage and then this is a more serious situation.
Other interesting anatomy facts on birds: They have a cleft palate –an opening called choana–that connects to their sinuses and nostrils. There trachea is made of complete cartilagenous rings so the trachea does not easily collapse. They do not have an epiglottis to cover the glottis–opening to the trachea. Unfortunately this makes inhalation of seeds a true concern. Bird tongues have a bone to aid their movement and manipulation of food. They have a less developed sense of taste than humans but they have additional touch recepters. Birds do have ears but they do not have pinnae or those outer flaps of ears that we associate ears. The ears are hidden by the feathers on the side of their heads.
Wow, I can keep going on bird anatomy but it is quite exhausting…so I think I will stop here for now. I think next week will have to be a small mammal blog week just for something different