Zunzún or bumblebee hummingbird shown here at 1.5 times actual size. Odds are good you'll spot one while visiting the island.
The zunzún is a hummingbird and the world's smallest warm-blooded vertebrate weighing between 1.6 and 1.8 grams. When flying, its wings beat 80 times per second, and when mating, up to 200 times per second. Its heart rate is the second fastest of all animals. Zunzúns also have the fewest feathers of all birds. Their daytime body temperature is 40°C (104°F), the highest of all birds. At night, it drops down to 19°C (66°F) to save energy. Zunzúns eat half their total body mass and drink eight times their weight in water daily. They are found in Cuban woodlands, shrubbery and gardens. Its nest is only 3 cm (1 in) in diameter. Its diet consists mainly of nectar and insects.
From Visit Cuba: