54 The largest living bird, the ostrich, lays an egg that is 4,500 times heavier than that of the smallest, the hummingbird. In the past, one of the heaviest birds that ever existed – the elephant bird – laid eggs that could each have swallowed up seven ostrich eggs with room to spare. The roc This fictional creature from Arabian Nights may be based on the huge, flightless elephant bird of Madagascar. Hummingbird egg Each egg weighs about one-fifth of the adult’s weight. Ostrich egg Each egg weighs up to 1.5 kg (3.3 lb) – about a hundredth of the adult’s weight. Ostrich Clubbing together The ostrich lays the largest egg of any bird alive today. These birds often lay their eggs in the same place, creating a pile of up to 50 eggs. Shell almost 2 mm thick Tiny eggs The smallest hummingbird eggs measure 1 cm (0.4 in) from end to end and weigh about 0.35 g (0.01 oz). The female lays only two eggs in the tiny nest. Hummingbirds Hummingbirds come in a variety of colours.