Bee hummingbird

The bee hummingbird or zunzuncito ("Mellisuga helenae") is a species of hummingbird. It lives in Cuba's Isla de la Juventud.
A newly hatched bee hummingbird chick may weigh about a fingernail clipping. Its weight is less than a tenth of an ounce (2 g). Because of this, it is the smallest living bird as well as the smallest theropod dinosaur on record. Females grow to up to long, weighing around . Male bee hummingbirds grow to be long, weighing around .
Male hummingbirds have a red throat and head, with long neck feathers. They have a light underside, spotted blue wing tips and black tipped tail feathers. The rest of the feathers are blue or green. Females have green parts and white tips to the tail feathers. After mating season, the birds become dull and gray in color.
When flying, bee hummingbirds beat 80 times a second. During courtship flight, they beat up to 200 times per second.
When they are hatched, they are blind and nearly naked. The mother feeds the hatchlings by regurgitating for 20-40 days while she stays over the nest. Only after their wing feathers are grown will the hatchlings leave the nest (around 23 days after hatching).