Hummingbirds are known for their vibrant, iridescent colors that shimmer in the sunlight. However, some species have more muted, brown plumage. There are several reasons why certain hummingbirds evolved brown feathers rather than flashy colors.
Camouflage
One of the main reasons some hummingbirds are brown is for camouflage. Brightly colored feathers may help attract mates, but they also make the birds more visible to predators. Species that live in wooded areas tend to be more brown and green in order to blend in with their surroundings. The camouflage helps conceal hummingbirds from birds of prey and other animals that may try to catch them.
For example, the brown violetear is a species found in dense forest habitats in Central and South America. As its name suggests, it has plain brown plumage on most of its body, providing good camouflage as it feeds among the trees and vegetation. Similarly, the brown woodland warbler and Geoffroy’s hermit are two other primarily brown hummingbird species that inhabit forests.
Heat Regulation
Another reason some hummingbirds have dull or brown feathers is that it helps them regulate body heat. Dark colors absorb more heat from sunlight compared to lighter, reflective colors. This extra heat absorption can be beneficial in colder environments or at higher elevations where temperatures are cooler.
Species like the brown incamate inhabit high mountain areas. Their darker brown plumage helps soak up heat from the weak high-altitude sunlight. Other brownish hummingbirds, like the rufous-breasted hermit, are found at cooler, higher latitudes compared to their tropical relatives and also utilize their dark feathers to stay warm.
Male vs. Female Plumage
In some hummingbird species, the difference in color between males and females results in females having more brown plumage. Males frequently have bright, colorful feathers for attracting females. But this conspicuous coloration could make females and their nests more obvious to predators.
Therefore, many hummingbird species exhibit sexual dimorphism, with females being less colorful than males. For example, male magnificent hummingbirds have a vibrant magenta throat, while females are primarily covered in gray-brown feathers. This helps camouflage the female while she incubates eggs and cares for chicks.
Age Differences
Younger hummingbirds can also display duller, brown plumage that differs from their adult coloration. Juveniles molt into their mature, adult feathers after their first year. Prior to this molt, their drab colors help conceal the vulnerable young birds through their early development until they can take on the brighter colors of adults.
The cinnamon hummingbird, for instance, has cinnamon-brown plumage as a juvenile. But after its first molt, the males attain their striking blue crowns and throats while the females remain primarily cinnamon-brown. This difference in juvenile versus adult plumage results in browner young birds.
Evolution of Brown Plumage
The evolution of boring brown feathers in certain hummingbird species when closely related ones have flashy colors likely comes down to environmental adaptations and sexual selection pressures. Species in forests adapted duller plumage over time as those better camouflaged were more successful. And in some species, natural selection has led to females in particular evolving more inconspicuous brown feathers while males retain their showy colors.
While brown may seem dull compared to ruby red throats or emerald green tails, these subtler feathers play an important role in the survival and evolution of different hummingbird species.
Examples of Brown Hummingbird Species
Here are some examples of hummingbird species that have primarily brown plumage:
- Brown violetear – Found in Central and South America in forest habitats
- Brown woodland warbler – Occurs in Mexico and Central America in lowland forests
- Buff-bellied hermit – Common in mountain forests of Costa Rica and Panama
- Rufous-breasted hermit – Ranges along the Andes mountains in woodland areas
- Allen’s hummingbird – Females and juveniles are brown, live along the Pacific Coast
- Sooty barbthroat – A Caribbean species, females are cinnamon-brown
- Geoffroy’s hermit – Males and females are brownish, found from Mexico to Bolivia
Geographic Range of Brown Hummingbirds
Brown hummingbirds live throughout the Americas in a variety of habitats:
- Tropical forests – Many brown species live in lowland and mountain tropical forests, like the brown violetear and buff-bellied hermit.
- Temperate forests – Some occupy temperate forests farther from the equator, like the rufous-breasted hermit.
- Coastal areas – Certain brown hummingbirds, including the Allen’s hummingbird, inhabit coastal areas.
- Caribbean islands – Examples found on Caribbean islands include the Antillean crested hummingbird and sooty barbthroat.
- Higher elevations – Brownish species like the brown incamate thrive at high Andean elevations.
So while they may not be as vibrantly colored, brown hummingbirds occupy a broad range of environments across the Western Hemisphere.
Habitat and Behavior
Compared to colorful tropical species, brown hummingbirds tend to prefer different habitat types:
- Forests – Most brown hummingbirds live in denser forest rather than open areas. The tree cover helps conceal them.
- Higher elevations – Some brown species inhabit high mountainous regions which can be cooler and more wooded.
- Less aggressive – They tend to be less aggressive than flashy tropical hummingbirds, which helps them blend in to their surroundings more.
- Generalist feeders – Brown species get nectar from a wider variety of flowers rather than specialized tropical flowers.
These behavioral differences from brighter hummingbirds likely help enhance the camouflage of brown species in their respective environments.
Interesting Facts about Brown Hummingbirds
- The female rusty-tailed hummingbird is cinnamon brown with a rusty reddish tail. Males have a colorful turquoise crown.
- Allen’s hummingbird juveniles are brown with streaks until their first molt when males attain their signature orange-red throat.
- The rufous-capped warbler is an unusual brown hummingbird species that nests on the ground rather than in trees.
- Many brown hummingbirds have a small amount of colorful iridescent feathers, often on the throat or crown.
- Some taxa like the cinnamon hummingbird were once considered brown subspecies but are now recognized as full species.
Threats and Conservation
Some brown hummingbird species face certain threats to their populations and habitat:
- Habitat loss from deforestation in tropical areas can severely impact forest-dwelling brown hummingbirds.
- Climate change may alter flower availability and force range shifts for species at higher elevations like the brown incamate.
- Nest predation from invasive species can threaten safety of nest sites.
- Collision hazards from human structures and activities are a problem for many hummingbirds.
While not yet considered threatened, protecting habitat and resources will be important for the continued survival of brown hummingbird species sharing ecosystems with humans.
Conclusion
Brown hummingbirds demonstrate that not all hummingbirds are brightly colored. Duller brown plumage can serve important functions like camouflage, heat regulation, and signalling gender or age differences. Brown-feathered species inhabit diverse environments across the Americas and have adapted their unique appearance, habitats, and behaviors for optimal survival in their ecological niches. While perhaps not as vibrant as other hummingbirds, these subtle-colored species play special roles in pollination and balancing tropical ecosystems. Understanding why some are brown reminds us that nature’s diversity goes beyond just showy flashes of color.
