The ostrich is the largest bird in the world, weighing on average 140-340 lbs and standing at 6-9 feet tall. The female ostrich lays her eggs in a single communal nest, a simple pit that is scraped out in the ground by the male. The dominant female lays her eggs first, and when it is time to cover them for incubation she discards extra eggs from the weaker females. A female ostrich can distinguish her own eggs from the others in a communal nest. Ostrich eggs are the largest of all eggs although though they are actually the smallest eggs relative to the size of the adult bird — on average they weigh 3 lbs. The females incubate the eggs by day and by the males by night. This uses the coloration of the two sexes to escape detection of the nest, as the drab female blends in with the sand, while the black male is nearly undetectable in the night.