In the world of ornithology, the competition for the title of “smallest” is a game of millimeters. While many people use the terms interchangeably, the Bee Hummingbird (Mellisuga helenae) and the Bumblebee Hummingbird (Atthis heloisa) are two distinct species with different ranges, appearances, and biological classifications.
This comparison breaks down the nuances of these two feathered “insects,” exploring how they survive at such extreme sizes and how to tell them apart in the field.
Measuring the Miniscule: World’s Two Smallest Birds
🐦 Bee Hummingbird (Cuba)
- Scientific Name: Mellisuga helenae
- Size: ~5.5 cm (2.1 in), 1.6–2.0 g — smallest bird in existence.
- Plumage:
- Males: iridescent green upperparts, fiery red throat (gorget) during breeding.
- Females: blue‑green upperparts, white underparts.
- Range: Endemic to Cuba and Isla de la Juventud.
- Habitat: Dense forests, gardens, shrublands with abundant flowers.
- Nesting: Tiny cup‑shaped nests on tree branches.
- Unique Fact: Heartbeat can exceed 1,200 beats per minute during flight.
🐦 Bumblebee Hummingbird (Mexico)
- Scientific Name: Selasphorus heloisa (formerly Atthis heloisa)
- Size: 5.9–7.5 cm (2.3–3.0 in), 2.0–2.7 g — slightly larger than Bee Hummingbird.
- Plumage:
- Males: metallic bronze‑green upperparts, magenta‑purple gorget, cinnamon flanks.
- Females: bronze‑green upperparts, white throat with bronze spots.
- Range: Endemic to Mexico, also found in Guatemala; occasional vagrants in the U.S.
- Habitat: Mountainous oak and coniferous forests, edges of woodlands.
- Nesting: Sheltered nests in shrubs or tree branches.
- Unique Fact: Despite size, capable of long territorial flights at high elevations.
1. The Title Holders: Defining the “Smallest”
Before comparing the two, we must establish their rankings in the record books.
- The Bee Hummingbird: This species is the undisputed smallest bird in the world. It is so small that it is often mistaken for a large bee or a hawk moth.
- The Bumblebee Hummingbird: While not the smallest in the world, it is the smallest bird in North America (specifically Mexico). It is only slightly larger than its Cuban cousin, often ranking as the second or third smallest bird globally.
2. Geographical Range: Where Do They Live?
One of the easiest ways to distinguish these birds is by looking at a map. Their natural habitats do not overlap.
The Bee Hummingbird (The Cuban Jewel)
This species is endemic to Cuba. It is found primarily in the Zapata Swamp, the Guanahacabibes Peninsula, and certain forested areas of the island. It prefers coastal forests and interior valleys where specific nectar-rich flowers are abundant.
The Bumblebee Hummingbird (The Mexican Miniature)
The Bumblebee Hummingbird is a mountain dweller native to Mexico. Its range extends from the highlands of Chihuahua and Nuevo León down to Oaxaca. It thrives in montane forests, pine-oak woodlands, and cloud forests, usually at elevations between 1,500 and 3,000 meters.
3. Physical Specifications: The Tale of the Tape
When dealing with birds this small, weight is measured in grams (roughly the weight of a paperclip) and length in centimeters.
| Feature | Bee Hummingbird | Bumblebee Hummingbird |
| Scientific Name | Mellisuga helenae | Atthis heloisa |
| Length | ~5.7 cm (2.2 in) | ~7.0 cm (2.7 in) |
| Weight | 1.6 to 2.0 grams | 2.2 to 2.7 grams |
| Wingspan | ~3.2 cm | ~3.5 cm |
| Bill Length | Very short / straight | Short / straight |
4. Visual Comparison: Color and Plumage
While both birds are iridescent, their color palettes and patterns differ significantly, especially in males during the breeding season.
Male Bee Hummingbird Appearance
- Gorget (Throat): During the breeding season, the male has a spectacular, iridescent fiery pink-to-red throat and head.
- Plumes: The feathers on the side of the throat extend into long, pointed plumes that look like “sideburns.”
- Body: The upper parts are bluish-green, while the underparts are mostly grayish-white.
Male Bumblebee Hummingbird Appearance
- Gorget (Throat): The male features a magenta-to-violet throat.
- Tail: Unlike the Bee Hummingbird, the Bumblebee Hummingbird has distinct rufous (reddish-brown) coloring on its outer tail feathers, which is a key identification feature.
- Body: It has a bronze-green back and a white chest with buff-colored flanks.
5. Behavioral Differences: Flight and Sound
Because they are so small, both species exhibit flight patterns that mimic insects more than birds, but they sound different to the trained ear.
- The Bee Hummingbird’s Wingbeat: Its wings beat roughly 80 times per second during normal flight, but this can increase to 200 times per second during courtship displays. The sound is a high-pitched “hum” that is almost at the edge of human hearing.
- The Bumblebee Hummingbird’s Sound: Its flight sound is often described as “dryer” or more “insect-like.” The male’s song is a series of high-pitched, thin whistles and chips, often delivered from a high, exposed perch in the Mexican cloud forests.
6. Diet and Foraging Habits
Both birds are “nectar specialists,” but their size limits which flowers they can access.
- Flower Selection: They prefer flowers with small, shallow tubes because their bills are relatively short compared to larger hummingbirds like the Sword-billed Hummingbird.
- Insect Consumption: To maintain their extreme metabolism, they eat a higher-than-average amount of tiny spiders and gnats. Because they are so small, they can hover in front of spiderwebs and “glean” insects directly from the silk without getting stuck.
7. Nesting and Reproduction
The scale of their reproduction is perhaps the most incredible aspect of their biology.
- The Nest: A Bee Hummingbird nest is roughly the size of half a walnut shell. It is constructed of lichen, cobwebs, and bark.
- The Eggs: Both species lay two eggs. In the Bee Hummingbird, these eggs are the size of coffee beans.
- Incubation: The female performs all the nesting duties. Due to their tiny size, the chicks are extremely vulnerable to large insects (like praying mantises) and even spiders.
Conservation Status: The Future Outlook
In 2026, both species face challenges, though one is significantly more vulnerable than the other.
- Bee Hummingbird (Near Threatened): Because it is limited only to Cuba, habitat loss from agriculture and climate-driven storms (hurricanes) poses a massive threat. Its population is currently in decline.
- Bumblebee Hummingbird (Least Concern): With a wider range across the Mexican highlands, this species is more stable. However, deforestation in the Mexican “Cloud Forests” is a growing concern for their long-term survival.
How to Spot Them: Tips for Birdwatchers
If you are traveling to see these “living jewels,” keep these tips in mind:
- Look for the “Hovering Insect”: If you see what you think is a bumblebee but it’s moving with extreme precision, look closer—it’s likely the bird.
- Listen for the “Squeak”: Both birds have very thin, high-pitched vocalizations that sound more like a cricket than a bird.
- Check the Tail (For Bumblebee): If you are in Mexico, look for that flash of rufous/orange in the tail as the bird maneuvers.
- Visit Coastal Cuba (For Bee): The best chance to see the Bee Hummingbird is in the early morning at the edges of the Cuban forests where the light hits the flowers.
Conclusion
While the Bee Hummingbird holds the crown for the smallest size, the Bumblebee Hummingbird is a close second and a master of the high-altitude Mexican forests. Both birds represent the absolute minimum size a warm-blooded vertebrate can achieve while maintaining the high-energy lifestyle of an aviator. Whether you are in the Zapata Swamp of Cuba or the pine-oaks of Mexico, seeing either of these birds is a reminder of the incredible diversity and “miniaturization” possible in the natural world.
FAQ: Frequently Asked Questions
1. Can a Bee Hummingbird be kept as a pet?
No. They have extremely specialized diets and metabolic needs. Furthermore, they are protected by international law and Cuban environmental regulations.
2. Why are they called “Bumblebee” or “Bee” hummingbirds?
Simply because of their size and the buzzing sound of their wings. To an untrained observer, they are indistinguishable from large insects at a distance.
3. Do they migrate?
The Bee Hummingbird is a permanent resident of Cuba. The Bumblebee Hummingbird is generally sedentary but may move to different altitudes (altitudinal migration) depending on the flowering season in Mexico.
4. Are they afraid of humans?
They are often quite bold because they are so fast; they likely view humans as slow-moving features of the landscape rather than immediate predators.
5. What is the biggest threat to these birds?
Habitat fragmentation. Because they are so small, they need high-density flower patches to survive. If the distance between “fueling stations” becomes too great, they cannot survive the journey.
6. Can I attract them to a feeder?
Yes, but they are often bullied away by larger, more aggressive hummingbirds. Using a “micro-feeder” with very small ports can sometimes help them get a turn at the nectar.
7. How long do they live?
Despite their high-speed lives, they can live 5 to 7 years in the wild, assuming they survive the first year of life.
8. Is the Bee Hummingbird the same as the Vervain Hummingbird?
No. The Vervain Hummingbird (Mellisuga minima) is the second smallest bird in the world, found in Hispaniola and Jamaica. It is slightly larger than the Bee Hummingbird.
How does the extreme size of these birds affect their ability to regulate body temperature during cold mountain nights?