Birds of different feathers!

Ostriches are the largest birds still in existence following the disappearance of the Aepyornis named Elephant-bird (Madagascar) and the  Dinornis named Moa (New Zealand) in the 15th century. 
Males can reach over 7 feet (2.40m) in height, and females approximately 5 feet (1.80m).

They live in groups with a dominant male, a dominant female, and other females. The females all lay eggs in a common nest, a hole in the ground, which is incubated by the male. When the chicks hatch, they can move around.

If we move to the other side of the bird spectrum in terms of diversity of form, color, and behavior, we find the hummingbirds, which are their complete opposites.

A white-booted racket-tail, for example, weighs about 0.14 oz (4 g), which is about the average weight of its fellows.

Due to their tiny legs, they can only land on branches. They spend most of their time flying, searching for food: nectar. Virtuosos of flight, they can forage without landing and some can even fly backwards.