The Bumblebee Hummingbird (Selasphorus heloisa) is a tiny, iridescent resident of Mexico's highlands, weighing barely more than a nickel. At 5.9–7.5 cm and 2–2.7 g, it is one of the smallest members of its family, yet its metallic bronze-green plumage and magenta-purple gorget make it a striking sight in the dappled light of montane forests. Found in pine-oak, evergreen, and cloudforest habitats between 1,500 and 3,000 m, this species is generally sedentary but shifts between forest types with the seasons. Its presence is often announced by a high, thin whine and the insect-like buzz of its wings, a sound that can be heard before the bird is seen.
Learn to identify
Adult male Bumblebee Hummingbird perched on a twig (photo by Dominic Sherony).
Learning lesson · openly licensed photographs, labelled by BirdBot; labels checked against the cited sources and approved by AI
Short, straight bill: short and blackish in both sexes. White spot behind eye: a small white spot in both sexes. Magenta gorget: rear feathers flare out and back. Whitish underparts: dull white, with cinnamon flanks. Tiny, with a pink-purple throat on males.
Females have white throats with bronze spots.
Sources: Birds of the World: Bumblebee Hummingbird (Introduction) · Wikipedia: Bumblebee hummingbird (revision 1379678571)
Photo: Dominic Sherony, CC BY-SA 2.0, via Wikimedia Commons; labels added by BirdBot.
Spotting a Bumblebee Hummingbird in the field relies on its minuscule size, short blackish bill, and a distinct white spot behind the eye. Males of the nominate subspecies (S. h. heloisa) are the most colorful, featuring metallic bronze-green upperparts and a gorget that shifts from magenta-purple to bluish-purple at the edges. Their flanks are a light reddish cinnamon, and the tail feathers are complex, with the outer feathers tipped in wide white bands. Females of the same subspecies are more subdued, with a white throat speckled with metallic bronze spots and flanks that are more heavily cinnamon-streaked than the male's.
Regional differences are significant for birders in western Mexico. The subspecies S. h. margarethae is slightly smaller and paler. Its males have a darker, amethyst-violet gorget and pure white underparts, lacking the grayish wash of the nominate. The flanks are a light buff rather than reddish cinnamon. Females of margarethae have smaller metallic spots on the throat and buff-colored flanks, with tail tips that are pure white rather than off-white. Knowing which subspecies to expect based on your location—central versus western Mexico—can help confirm a quick glimpse.
The Bumblebee Hummingbird is a specialist of Mexico's major mountain ranges, where it thrives in the interiors, edges, and clearings of semi-humid to humid pine-oak and evergreen forests. It also frequents cloudforests and humid scrublands, typically between 1,500 and 3,000 m (4,900–9,800 ft) in elevation. The nominate subspecies ranges across the eastern and central highlands, from Tamaulipas in the northeast down through the transvolcanic belt to Guerrero and Oaxaca in the south. The western subspecies, S. h. margarethae, occupies the Sierra Madre Occidental, stretching from Sinaloa and Chihuahua to Jalisco. A single, rare record exists from the Huachuca Mountains in southeastern Arizona, but the species is otherwise considered endemic to Mexico.
While generally considered a resident, the Bumblebee Hummingbird is not strictly sedentary. It makes seasonal movements between pine-oak forests and cloudforests, likely tracking the availability of nectar and insects. This subtle shift in habitat use means birders may find the bird at slightly different elevations or in different forest types depending on the time of year.
This hummingbird is an opportunistic forager, visiting a wide variety of flowering plants. It prefers to feed at low to middle vegetation levels, hovering in a horizontal posture with its tail cocked up. Despite its small size, it is often dominated by larger hummingbirds, but it can slip into their territories to feed without confrontation. In addition to nectar, it gleans small arthropods from foliage, a behavior that is easier to spot if you watch the bird's movements closely.
Courtship is a visual spectacle: males hover in front of females, spreading their gorget and cocking their tails while making rhythmic vertical movements. Breeding activity varies by region; specimens in breeding condition have been collected from April to July and in December, while a study in Oaxaca noted nesting from late January to early March. The nest is a small cup of moss and lichen, often built on a thin branch of an avocado tree about 10 m (30 ft) above the ground. Incubation and fledging times remain unknown.
The Bumblebee Hummingbird's song is a high, thin, whining "sss ssssssssis" or "seeuuuuu" that is drawn out and fades at the end. It is typically sung from a perch, often in the understory. Its calls are high chips, similar to those of other Selasphorus species. One of the most distinctive sounds is the insect-like buzz produced by the male's wings in flight, which becomes noticeably louder during the courtship display. Listening for this buzz can be a reliable way to locate the bird in dense vegetation.
Because the Bumblebee Hummingbird is small and often hidden in the understory, patience is key. Focus your search on low-hanging flowers in pine-oak edges and clearings, where the bird favors feeding at middle vegetation heights. Look for the characteristic horizontal hovering posture with the tail cocked up. Since the bird is easily stressed, observe quietly from a distance using binoculars or a telephoto lens. Avoid approaching nesting sites, especially during the breeding season, and respect local regulations and private property when accessing these montane habitats.
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