All birds lay eggs.Humming birds lay the smallest eggs.The eggs of the bee hummingbird are about 0.2 inches long.
Ostriches lay the biggest birds eggs.They can weigh up to 5.5 pounds,and are so hard that a human adult can stand on them without breaking them.
Not all eggs are white or brown.The thrush,bullfinch,starling and blackbird are species that lay blue eggs.
Emus lay green eggs,Oystercatchers speckled eggs.
All birds are warm-blooded.There are only two bird species that can reduce their body temperature.
One of them is the humming bird.It always needs energy, but it can't eat during the night. Therefore, it reduces its body temperature and enters a kind of nighttime torpor.
The common poorwill also is an exception. It hibernates for several weeks a temperature lower than 50 degrees Fahrenheit.
ostrich 鸵鸟
thrush 鸫鸟
bullfinch 红腹灰雀
starling 椋鸟
blackbird 乌鸫
Oystercatchers 蛎鹬
speckled 有斑点的
poorwill 弱夜鹰
