Hummingbirds lay the smallest eggs ,the eggs (of bee) Hummingbirds are about 0.2 inches long .Ostrich lay the biggest birds  eggs ,they can weigh up to 5.5 pounds .and they 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 bird species that lay blue eggs .(Emus) ,lay green eggs ,Oyster catchers ,speckled eggs . All birds are warm-blooded ),there are only two bird species  that can reduce their body temperature .one of them is the Hummingbirds ,it always needs its energy but they can’t eat during the night , therefore it’ll reduce their 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  15 degrees Fahrenheit  speckled 有斑点的 hibernates 冬眠 torpor 不活泼