Are Birds Mammals? A Detailed Guide to Bird Classification

Birds are not mammals. Mammals are all viviparous and can secrete milk through mammary glands to nurse their young, such as pigs, cows, sheep, and so on; these animals are all beasts. Birds, however, are oviparous animals; they mainly lay eggs, which then hatch into young birds.

1. When do birds lay eggs?

Birds generally lay eggs in spring or summer, which then hatch into young birds; they rarely lay eggs in winter. This is because spring and summer are warm and food is plentiful. Among them, the African ostrich is the largest bird in the world; the eggs it lays are similar in color to duck eggs, 15-20 cm in diameter, weighing up to 1400 grams, and are the largest among bird eggs. The eggshell is very hard and can withstand the weight of a person.

2. How long does it take for bird eggs to hatch?

Different bird species have different incubation times. For parrots, the incubation period is generally 28 days, ducks 28 days, cranes and storks 27 days, chickens 21 days, and for pigeons, the incubation period is about 16 days.