A countercurrent heat exchanger allows the blood returning to the body core to be preheated before entering the core. Bird can shiver to keep temperature up. Nervous and Sensory Systems Birds have good vision and poor olfaction . However, vultures can locate carrion by olfactory means. The eyes are large relative to the skull.
Hearing is acute in some owls for prey locating.
Draw a picture of ear asymmetry. Desert birds use salt glands to conserve water. All birds are oviparous. Fertilization occurs and then eggs travel down the oviduct. In different regions albumin, yolk, and then the shell are secreted.