BUCKBEAK

'Buckbeak' (later renamed 'Witherwings') is a hippogriff, a magical beast in the fictional ''Harry Potter'' book series by J. K. Rowling.
Buckbeak, along with eleven other hippogriffs, is introduced during one of Hagrid's Care of Magical Creatures classes. Hagrid explains that hippogriffs are very calm, powerful giants, but are touchy creatures and demand respect. One must bow and keep eye contact before approaching. Harry successfully approaches Buckbeak, who allows him to ride him around the paddock. He still must bow on subsequent encounters, though Buckbeak apparently had taken a great liking to Harry from then on.
In the stories, Buckbeak is an enormous animal. Hippogriffs are bred, and are born with the appearance of a hybrid of bird and horse. Buckbeak looks to be a fusion of a giant Harpy Eagle and a gray horse, with a wingspan of nearly 20 feet. Horses generally weigh between 1300 and 2000 pounds, but because of his bird characteristics, he is lighter at just under half of a ton.

Draco Malfoy, in an arrogant attempt to show up his school nemesis, endeavours to approach Buckbeak as well. It becomes obvious that the Slytherin neither listened to nor cared about Hagrid's warnings about the hippogriffs' touchiness, as he makes contemptuous remarks about Buckbeak. Quickly angered, Buckbeak slashes Draco's arm with his claws.
Pretending to be injured much more severely than he truly is, Draco persuades his father, Lucius Malfoy, to use his political power to sentence Buckbeak to death. Hagrid's numerous appeals fail, and Walden Macnair of the Committee for the Disposal of Dangerous Creatures comes to Hogwarts to execute Buckbeak. With the use of a time-turner, Hermione and Harry free Buckbeak and rescue Sirius Black from the tower in which he was being held before being handed over to the dementors. Sirius escapes with Buckbeak and flies to safety.
During most of Harry's fourth year, Sirius and Buckbeak hide in a cave in the mountains above Hogsmeade. After this, they move to Number 12 Grimmauld Place, whereupon Buckbeak stays in Sirius' mother's former room.
In ''Harry Potter and the Half-Blood Prince'', Harry inherits Buckbeak, and allows Hagrid to look after him again. To avoid suspicion from the Ministry of Magic, he is given the alias Witherwings (Hagrid also calls Buckbeak by the nickname "Beaky"). A fiercely loyal creature, Buckbeak chased away Professor Snape from Harry by slashing his claws at the end of ''Half-Blood Prince''. Buckbeak also features in the Battle of Hogwarts at the end of ''Harry Potter and the Deathly Hallows'' leading the Hogwarts' Thestrals against Voldemort's giants.
This was also portrayed in the movie “Harry Potter and the Prisoner of Azkaban” in which Harry saves it from execution by taking away from Hagrids hut with the help of time turner. Harry saves sirius by helping him to escape on buckbeak.
The withers are the highest part of a horse's back, just above the shoulders. Witherwings, being a hippogriff, has wings on his withers, which explains the choice of name.
In the ''Prisoner of Azkaban'' film, during the scene where we first meet Buckbeak the Hippogriff, just after Ron pushes Harry forward there is a shot of the animal defecating. The CGI team believes this might be the first example of a CGI animal doing this, but the BBC miniseries ''Walking with Dinosaurs'' (1999) did so 5 years before.