There are more than 300 species of hummingbird and they vary in size; though only a few are more than 15 retentiveness long. The smallest (shown here in actual size) is the bee hummingbird, which is a native of Cuba. An average adult male measures only 5 centimeters in total length, half of which is taken up by the bill and tail. This tiny flier weighs only 1.6 grams. It builds a thimble-size nest and its egg is less than 1 centimeter in length.
Bee Hummingbird (Wikipedia)