The Peregrine Falcon is a very popular bird of prey. It resides everywhere in the world and moves from place to place. This makes the peregrine falcon the world’s It is the fastest animal alive and obviously, the fastest bird. It can reach speeds up to 242 mph! Birds have a four-chambered heart which contain two ventricles and two atria just like humans. The heart also contains a pericardial sac which contains serous fluid which is used for lubrication. This serous fluid is used to help in digestion, excretion, and respiration. The aortic arch is where the main arteries originate from and take it throughout the body. The postcava receives blood from the limbs of the bird through the renal portal system. The red blood cells that carry oxygen retain the nucleus through their whole lives.