The Bee Hummingbird (Mellisuga helenae) holds the record as the smallest living bird species on Earth. This tiny creature, known as the zunzuncito in its native land, challenges the biological limits of warm-blooded animals. Its existence is a remarkable display of specialized evolution and high-energy demands condensed into a diminutive package.
Defining Characteristics: Size and Appearance
The Bee Hummingbird’s dimensions are astonishingly small. The male averages a length of 5.5 centimeters, which includes its beak and tail. The female is slightly larger, reaching up to 6.1 centimeters in length. The male weighs only about 1.95 grams, while the female weighs around 2.6 grams.
This species exhibits marked sexual dimorphism, particularly during the breeding season. The male has a vibrant, iridescent gorget, or throat patch, that is bright reddish-pink to crimson, complemented by a bluish-green body. The female has a less striking appearance, featuring bluish-green upper parts and a pale gray underside, with distinctive white tips on her outer tail feathers.
Geographic Range and Preferred Habitat
The Bee Hummingbird is endemic to the entire Cuban archipelago, including the main island of Cuba and the Isla de la Juventud. Their distribution across Cuba, however, is fragmented and concentrated in specific areas.
They prefer habitats characterized by dense vegetation, such as coastal forests, dense woodlands, and swampy areas like the Zapata Swamp. The birds are often encountered in areas with abundant native flowering plants, which are necessary for their specialized diet. They also inhabit the isolated steep-sided hills known as mogotes found in Pinar del Río Province.
Specialized Diet and Metabolism
The survival of the Bee Hummingbird depends entirely on a high-energy diet to fuel its extraordinarily high metabolism. Its primary food source is nectar, which provides the necessary sugars to sustain its active lifestyle. They are known to feed from at least ten different native Cuban plant species.
To meet their intense energy needs, they must consume a massive amount of food daily, eating up to half their body weight in food. They also supplement their diet by consuming small insects and spiders, which provide essential protein. Their wings beat at an astonishing rate, sometimes up to 80 times per second during normal flight.
When they are not actively foraging, particularly at night, Bee Hummingbirds must conserve energy through a state called torpor. Torpor is a temporary, deep sleep state where the bird’s metabolic rate slows dramatically. This allows their body temperature and heart rate to drop significantly, preventing starvation when they cannot feed. This physiological adaptation is crucial for surviving the nightly fast.
Conservation Status and Threats
The International Union for Conservation of Nature (IUCN) currently classifies the Bee Hummingbird as Near Threatened. This designation indicates that the species is at risk of becoming vulnerable to extinction in the near future. The main pressure on their population comes from habitat loss.
Deforestation and the conversion of native vegetation for agricultural use in Cuba are steadily reducing the bird’s preferred forest and swamp habitats. Their reliance on a limited number of native plant species for nectar makes them particularly susceptible to environmental changes. Their miniature size also makes them vulnerable to various predators, including tropical spiders, frogs, and introduced species like the mongoose.