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. There are 2 kinds of polygamy. Ninety percent of bird species are monogamous and a few species such as some raptors and geese and swans mate for life. This is female enforced monogamy, meaning that females require help in the rearing process or there will be no success at all. Monogamous species usually hatch altricial young.